1
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Saetta C, Barlocco I, Liberto GD, Pacchioni G. Key Ingredients for the Screening of Single Atom Catalysts for the Hydrogen Evolution Reaction: The Case of Titanium Nitride. Small 2024:e2401058. [PMID: 38671564 DOI: 10.1002/smll.202401058] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2024] [Revised: 04/10/2024] [Indexed: 04/28/2024]
Abstract
A computational screening of Single Atom Catalysts (SACs) bound to titanium nitride (TiN) is presented, for the Hydrogen Evolution Reaction (HER), based on density functional theory. The role of fundamental ingredients is explored to account for a reliable screening of SACs. Namely, the formation of H2-complexes besides the classical H* one impacts the predicted HER activity, in line with previous studies on other SACs. Also, the results indicate that one needs to adopt self-interaction-corrected functionals. Finally, predicting an active catalyst is of little help without an assessment of its stability. Thus, it is included in the theoretical framework the analysis of the stability of the SACs in working conditions of pH and voltage. Once unconventional intermediates and stability are considered in a self-interaction corrected scheme, the number of potential good catalysts for HER is strongly reduced since i) some potentially good catalysts are not stable against dissolution and ii) the formation of unconventional intermediates leads to thermodynamic barriers. This study highlights the importance of including ingredients for the prediction of new systems, such as the formation of unconventional intermediates, estimating the stability of SACs, and the adoption of self-interaction corrected functionals. Also, this study highlights some interesting candidates deserving of dedicated work.
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Affiliation(s)
- Clara Saetta
- Dipartimento di Scienza dei Materiali, Università degli studi di Milano Bicocca, Via R. Cozzi 55, Milano, 20125, Italy
| | - Ilaria Barlocco
- Dipartimento di Scienza dei Materiali, Università degli studi di Milano Bicocca, Via R. Cozzi 55, Milano, 20125, Italy
| | - Giovanni Di Liberto
- Dipartimento di Scienza dei Materiali, Università degli studi di Milano Bicocca, Via R. Cozzi 55, Milano, 20125, Italy
| | - Gianfranco Pacchioni
- Dipartimento di Scienza dei Materiali, Università degli studi di Milano Bicocca, Via R. Cozzi 55, Milano, 20125, Italy
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2
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Misra D, Di Liberto G, Pacchioni G. CO 2 electroreduction on single atom catalysts: the role of the DFT functional. Phys Chem Chem Phys 2024; 26:10746-10756. [PMID: 38516878 DOI: 10.1039/d4cp00175c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/23/2024]
Abstract
One key process involving single atom catalysts (SACs) is the electroreduction of CO2 to fuels. The chemistry of SACs differs largely from that of extended catalytic surfaces, presenting an opportunity to improve the ability to activate very stable molecules, such as CO2. In this work, we performed a density functional theory (DFT) study of CO2 activation on a series of SACs, focusing on the role played by the adopted functional in activity predictions. The role of the exchange-correlation functional has been widely investigated in heterogenous catalysts, but it is less explored in SACs. We tested the widely used PBE and the PBE+U corrected functionals against the more robust hybrid PBE0 functional. The results show that PBE is reliable if one is interested in qualitative predictions, but it leads to some inaccuracies in other cases. A possible way to attenuate this effect is by adopting the PBE+U framework, as it gives results that are very similar to PBE0 at an acceptable computational cost. The results of this study further underline the importance of the computational framework adopted in predicting the activity of SACs. The work suggests that one needs to go beyond PBE for quantitative estimates, an important consideration when performing screening and high-throughput calculations.
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Affiliation(s)
- Debolina Misra
- Department of Physics, Indian Institute of Information Technology, Design and Manufacturing, Kancheepuram, Chennai 600127, India
| | - Giovanni Di Liberto
- Dipartimento di Scienza dei Materiali, Università di Milano - Bicocca, via R. Cozzi 55, Milano 20125, Italy.
| | - Gianfranco Pacchioni
- Dipartimento di Scienza dei Materiali, Università di Milano - Bicocca, via R. Cozzi 55, Milano 20125, Italy.
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3
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Ruta V, Di Liberto G, Moriggi F, Ivanov YP, Divitini G, Bussetti G, Barbera V, Bajada MA, Galimberti M, Pacchioni G, Vilé G. Copper Single Atoms Chelated on Ligand-Modified Carbon for Ullmann-Type C-O Coupling. ChemSusChem 2024; 17:e202400202. [PMID: 38350713 DOI: 10.1002/cssc.202400202] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/15/2024]
Abstract
Invited for this month's cover is the group of Gianvito Vilé at the Politecnico di Milano. The ChemSusChem cover image depicts in an artistic manner the concept of ligand entrapping of isolated metals to design single-atom catalysts. The Research Article itself is available at 10.1002/cssc.202301529.
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Affiliation(s)
- Vincenzo Ruta
- Department of Chemistry, Materials, and Chemical Engineering, "Giulio Natta" Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133, Milano, Italy
| | - Giovanni Di Liberto
- Department of Materials Science, Università degli Studi di Milano-Bicocca, Via Roberto Cozzi 55, 20125, Milano, Italy
| | - Francesco Moriggi
- Department of Chemistry, Materials, and Chemical Engineering, "Giulio Natta" Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133, Milano, Italy
| | - Yurii P Ivanov
- Electron Spectroscopy and Nanoscopy, Italian Institute of Technology, Via Morego 30, 16163, Genova, Italy
| | - Giorgio Divitini
- Electron Spectroscopy and Nanoscopy, Italian Institute of Technology, Via Morego 30, 16163, Genova, Italy
| | - Gianlorenzo Bussetti
- Department of Physics, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133, Milano, Italy
| | - Vincenzina Barbera
- Department of Chemistry, Materials, and Chemical Engineering, "Giulio Natta" Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133, Milano, Italy
| | - Mark A Bajada
- Department of Chemistry, Materials, and Chemical Engineering, "Giulio Natta" Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133, Milano, Italy
| | - Maurizio Galimberti
- Department of Chemistry, Materials, and Chemical Engineering, "Giulio Natta" Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133, Milano, Italy
| | - Gianfranco Pacchioni
- Department of Materials Science, Università degli Studi di Milano-Bicocca, Via Roberto Cozzi 55, 20125, Milano, Italy
| | - Gianvito Vilé
- Department of Chemistry, Materials, and Chemical Engineering, "Giulio Natta" Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133, Milano, Italy
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4
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Ruta V, Di Liberto G, Moriggi F, Ivanov YP, Divitini G, Bussetti G, Barbera V, Bajada MA, Galimberti M, Pacchioni G, Vilé G. Copper Single Atoms Chelated on Ligand-Modified Carbon for Ullmann-type C-O Coupling. ChemSusChem 2024; 17:e202301529. [PMID: 38050778 DOI: 10.1002/cssc.202301529] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2023] [Revised: 12/01/2023] [Accepted: 12/04/2023] [Indexed: 12/06/2023]
Abstract
Cross-coupling reactions are of great importance in chemistry due to their ability to facilitate the construction of complex organic molecules. Among these reactions, the Ullmann-type C-O coupling between phenols and aryl halides is particularly noteworthy and useful for preparing diarylethers. However, this reaction typically relies on homogeneous catalysts that rapidly deactivate under harsh reaction conditions. In this study, we introduce a novel heterogeneous catalyst for the Ullmann-type C-O coupling reaction, comprised of isolated Cu atoms chelated to a tetraethylenepentamine-pyrrole ligand that is immobilized on graphite nanoplatelets. The catalytic study reveals the recyclability of the material, and demonstrates the crucial role of the pyrrole linker in stabilizing the Cu sites. The work expands the potential of single-atom catalyst nanoarchitectures and underscores the significance of ligands in stabilizing metals in cationic forms, providing a novel, tailored catalyst for cross-coupling chemistries.
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Affiliation(s)
- Vincenzo Ruta
- Department of Chemistry, Materials, and Chemical Engineering, "Giulio Natta" Politecnico di Milano, Piazza Leonardo da Vinci 32, IT-20133, Milano, Italy
| | - Giovanni Di Liberto
- Department of Materials Science, Università degli Studi di Milano-Bicocca, Via Roberto Cozzi 55, IT-20125, Milano, Italy
| | - Francesco Moriggi
- Department of Chemistry, Materials, and Chemical Engineering, "Giulio Natta" Politecnico di Milano, Piazza Leonardo da Vinci 32, IT-20133, Milano, Italy
| | - Yurii P Ivanov
- Electron Spectroscopy and Nanoscopy, Italian Institute of Technology, Via Morego 30, IT-16163, Genova, Italy
| | - Giorgio Divitini
- Electron Spectroscopy and Nanoscopy, Italian Institute of Technology, Via Morego 30, IT-16163, Genova, Italy
| | - Gianlorenzo Bussetti
- Department of Physics, Politecnico di Milano, Piazza Leonardo da Vinci 32, IT-20133, Milano, Italy
| | - Vincenzina Barbera
- Department of Chemistry, Materials, and Chemical Engineering, "Giulio Natta" Politecnico di Milano, Piazza Leonardo da Vinci 32, IT-20133, Milano, Italy
| | - Mark A Bajada
- Department of Chemistry, Materials, and Chemical Engineering, "Giulio Natta" Politecnico di Milano, Piazza Leonardo da Vinci 32, IT-20133, Milano, Italy
| | - Maurizio Galimberti
- Department of Chemistry, Materials, and Chemical Engineering, "Giulio Natta" Politecnico di Milano, Piazza Leonardo da Vinci 32, IT-20133, Milano, Italy
| | - Gianfranco Pacchioni
- Department of Materials Science, Università degli Studi di Milano-Bicocca, Via Roberto Cozzi 55, IT-20125, Milano, Italy
| | - Gianvito Vilé
- Department of Chemistry, Materials, and Chemical Engineering, "Giulio Natta" Politecnico di Milano, Piazza Leonardo da Vinci 32, IT-20133, Milano, Italy
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Dao V, Di Liberto G, Yadav S, Uthirakumar P, Chen K, Pacchioni G, Lee IH. Pt Single Atoms Supported on Defect Ceria as an Active and Stable Dual-Site Catalyst for Alkaline Hydrogen Evolution. Nano Lett 2024; 24:1261-1267. [PMID: 38242169 DOI: 10.1021/acs.nanolett.3c04237] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2024]
Abstract
This work evaluates the feasibility of alkaline hydrogen evolution reaction (HER) using Pt single-atoms (1.0 wt %) on defect-rich ceria (Pt1/CeOx) as an active and stable dual-site catalyst. The catalyst displayed a low overpotential and a small Tafel slope in an alkaline medium. Moreover, Pt1/CeOx presented a high mass activity and excellent durability, competing with those of the commercial Pt/C (20 wt %). In this picture, the defective CeOx is active for water adsorption and dissociation to create H* intermediates, providing the first site where the reaction occurs. The H* intermediate species then migrate to adsorb and react on the Pt2+ isolated atoms, the site where H2 is formed and released. DFT calculations were also performed to obtain mechanistic insight on the Pt1/CeOx catalyst for the HER. The results indicate a new possibility to improve the state-of-the-art alkaline HER catalysts via a combined effect of the O vacancies on the ceria support and Pt2+ single atoms.
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Affiliation(s)
- Vandung Dao
- Department of Materials Science and Engineering, Korea University, Seoul 02841, Republic of Korea
| | - Giovanni Di Liberto
- Dipartimento di Scienza dei Materiali, Università degli Studi di Milano-Bicocca, Via Roberto Cozzi 55, Milano 20125, Italy
| | - Sunny Yadav
- Department of Materials Science and Engineering, Korea University, Seoul 02841, Republic of Korea
| | - Periyayya Uthirakumar
- Department of Materials Science and Engineering, Korea University, Seoul 02841, Republic of Korea
| | - Kai Chen
- Department of Materials Science and Engineering, Korea University, Seoul 02841, Republic of Korea
| | - Gianfranco Pacchioni
- Dipartimento di Scienza dei Materiali, Università degli Studi di Milano-Bicocca, Via Roberto Cozzi 55, Milano 20125, Italy
| | - In-Hwan Lee
- Department of Materials Science and Engineering, Korea University, Seoul 02841, Republic of Korea
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6
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Di Liberto G, Pacchioni G. Modeling Single-Atom Catalysis. Adv Mater 2023; 35:e2307150. [PMID: 37749881 DOI: 10.1002/adma.202307150] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Revised: 08/17/2023] [Indexed: 09/27/2023]
Abstract
Electronic structure calculations represent an essential complement of experiments to characterize single-atom catalysts (SACs), consisting of isolated metal atoms stabilized on a support, but also to predict new catalysts. However, simulating SACs with quantum chemistry approaches is not as simple as often assumed. In this work, the essential factors that characterize a reliable simulation of SACs activity are examined. The Perspective focuses on the importance of precise atomistic characterization of the active site, since even small changes in the metal atom's surroundings can result in large changes in reactivity. The dynamical behavior and stability of SACs under working conditions, as well as the importance of adopting appropriate methods to solve the Schrödinger equation for a quantitative evaluation of reaction energies are addressed. The Perspective also focuses on the relevance of the model adopted. For electrocatalysis this must include the effects of the solvent, the presence of electrolytes, the pH, and the external potential. Finally, it is discussed how the similarities between SACs and coordination compounds may result in reaction intermediates that usually are not observed on metal electrodes. When these aspects are not adequately considered, the predictive power of electronic structure calculations is quite limited.
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Affiliation(s)
- Giovanni Di Liberto
- Dipartimento di Scienza dei Materiali, Università degli studi di Milano Bicocca, Via R. Cozzi 55, Milano, 20125, Italy
| | - Gianfranco Pacchioni
- Dipartimento di Scienza dei Materiali, Università degli studi di Milano Bicocca, Via R. Cozzi 55, Milano, 20125, Italy
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7
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Barlocco I, Maleki F, Pacchioni G. CO2 activation on Cu/TiO2 nanostructures: importance of dual binding site. Chemistry 2023:e202300757. [PMID: 37021391 DOI: 10.1002/chem.202300757] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2023] [Revised: 04/04/2023] [Accepted: 04/06/2023] [Indexed: 04/07/2023]
Abstract
CO2 adsorption and activation on Cu single atom catalysts and Cu nanoclusters supported on the (110) surface of rutile and on the (101) surface of anatase TiO2 has been investigated by means of first principles electronic structure calculations. The role of oxide reduction associated to the presence of oxygen vacancies has been considered. Five main messages emerge from this study. (1) CO2 activation on Cu/TiO2 nanostructures is surface sensitive, as the rutile and anatase surfaces can exhibit different behaviours; (2) the surface morphology is essential since CO2 is activated only when the molecule can simultaneously bind to at least two active sites, such as a Cu atom on one side and an oxide ion on the other site; (3) Cu atoms on TiO2 are in +I oxidation state and can bind and activate CO2 via charge transfer from the oxide; (4) on supported Cu clusters CO2 activation occurs mostly at the metal/oxide interface; (5) the presence of O vacancy sites facilitates the spontaneous dissociation of CO2 to CO, or increases the electron density of the metal catalyst, two effects that can influence the mechanism of CO2 reduction to methanol or other chemicals.
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Affiliation(s)
- Ilaria Barlocco
- University of Milano-Bicocca: Universita degli Studi di Milano-Bicocca, Dipartimento di Scienza dei Materiali, ITALY
| | - Farahnaz Maleki
- University of Milano-Bicocca: Universita degli Studi di Milano-Bicocca, Dipartimento di Scienza dei Materiali, ITALY
| | - Gianfranco Pacchioni
- Università degli Studi di Milano-Bicocca, Dipartimento di Scienza dei Materiali, U05, Piano: P02, Stanza: 2073, Via Roberto Cozzi 55, 20125, Milano, ITALY
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8
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Maleki F, Di Liberto G, Pacchioni G. pH- and Facet-Dependent Surface Chemistry of TiO 2 in Aqueous Environment from First Principles. ACS Appl Mater Interfaces 2023; 15:11216-11224. [PMID: 36786774 PMCID: PMC9982820 DOI: 10.1021/acsami.2c19273] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Accepted: 02/02/2023] [Indexed: 06/18/2023]
Abstract
TiO2 is a relevant catalytic material, and its chemistry in aqueous environment is a challenging aspect to address. Also, the morphology of TiO2 particles at the nanoscale is often complex, spanning from faceted to spherical. In this work, we study the pH- and facet-dependent surface chemistry of TiO2/water interfaces by performing ab initio molecular dynamics simulations with the grand canonical formulation of species in solution. We first determined the acid-base equilibrium constants at the interface, which allows us to estimate the pH at the point of zero charge, an important experimental observable. Then, based on simulated equilibrium constants, we predict the amount of H+, OH-, and adsorbed H2O species present on the surfaces as a function of the pH, a relevant aspect for water splitting semi-reactions. We approximated the complex morphology of TiO2 particles by considering the rutile (110) and (011), and anatase (101), (001), and (100) surfaces.
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9
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Fuhrich A, Paier J, Tosoni S, Leandro Lewandowski A, Gura L, Schneider W, Pacchioni G, Freund H. Mixed Germania‐Silica Films on Ru(0001): A combined experimental and theoretical study. Isr J Chem 2023. [DOI: 10.1002/ijch.202300005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/25/2023]
Affiliation(s)
- Alexander Fuhrich
- Fritz Haber Institute of the Max Planck Society 14195 Berlin Germany
| | - Joachim Paier
- Fritz Haber Institute of the Max Planck Society 14195 Berlin Germany
| | - Sergio Tosoni
- Accademia Nazionale dei Lincei Universita' degli Studi di Milano-Bicocca Dipartimento di Scienza dei Materiali 20125 Milano Italy
| | | | - Leonard Gura
- Fritz Haber Institute of the Max Planck Society 14195 Berlin Germany
| | | | - Gianfranco Pacchioni
- Accademia Nazionale dei Lincei Universita' degli Studi di Milano-Bicocca Dipartimento di Scienza dei Materiali 20125 Milano Italy
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10
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Schewe N, Maleki F, Di Liberto G, Gerdes A, Idriss H, Pacchioni G, Wöll C. Identification of Intermediates in the Reaction Pathway of SO 2 on the CaO Surface: From Physisorption to Sulfite to Sulfate. Chemistry 2023; 29:e202203956. [PMID: 36645202 DOI: 10.1002/chem.202203956] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2022] [Revised: 01/14/2023] [Accepted: 01/16/2023] [Indexed: 01/17/2023]
Abstract
The interaction of CaO and Ca(OH)2 with solvated or gaseous SO2 plays a crucial role in the corrosion of urban infrastructure by acid rain or in the removal of SO2 from flue gas. We carried out a combined spectroscopic and theoretical investigation on the interaction of SO2 with a CaO(001) single crystal. First, the surface chemistry of SO2 was investigated at different temperatures using polarization-resolved IR reflection absorption spectroscopy. Three species were identified, and an in-depth density functional theory study was carried out, which allowed deriving a consistent picture. Unexpectedly, low temperature exposure to SO2 solely yields a physisorbed species. Only above 100 K, the transformation of this weakly bound adsorbate first to a chemisorbed sulfite and then to a sulfate occurs, effectively passivatating the surface. Our results provide the basis for more efficient strategies in corrosion protection of urban infrastructure and in lime-based desulfurization of flue gas.
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Affiliation(s)
- Nils Schewe
- Institute of Functional Interfaces (IFG), Karlsruhe Institute of Technology (KIT), 76344, Eggenstein-Leopoldshafen, Germany
| | - Farahnaz Maleki
- Department of Materials Science, University of Milano-Bicocca, 20125, Milano, Italy
| | - Giovanni Di Liberto
- Department of Materials Science, University of Milano-Bicocca, 20125, Milano, Italy
| | - Andreas Gerdes
- Institute of Functional Interfaces (IFG), Karlsruhe Institute of Technology (KIT), 76344, Eggenstein-Leopoldshafen, Germany
| | - Hicham Idriss
- Institute of Functional Interfaces (IFG), Karlsruhe Institute of Technology (KIT), 76344, Eggenstein-Leopoldshafen, Germany
| | - Gianfranco Pacchioni
- Department of Materials Science, University of Milano-Bicocca, 20125, Milano, Italy
| | - Christof Wöll
- Institute of Functional Interfaces (IFG), Karlsruhe Institute of Technology (KIT), 76344, Eggenstein-Leopoldshafen, Germany
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11
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Barlocco I, Cipriano LA, Di Liberto G, Pacchioni G. Does the Oxygen Evolution Reaction follow the classical OH*, O*, OOH* path on single atom catalysts? J Catal 2023. [DOI: 10.1016/j.jcat.2022.12.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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12
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Cipriano LA, Di Liberto G, Pacchioni G. Superoxo and Peroxo Complexes on Single-Atom Catalysts: Impact on the Oxygen Evolution Reaction. ACS Catal 2022. [DOI: 10.1021/acscatal.2c03020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Luis A. Cipriano
- Dipartimento di Scienza dei Materiali, Università di Milano─Bicocca, Via Roberto Cozzi 55, 20125 Milano, Italy
| | - Giovanni Di Liberto
- Dipartimento di Scienza dei Materiali, Università di Milano─Bicocca, Via Roberto Cozzi 55, 20125 Milano, Italy
| | - Gianfranco Pacchioni
- Dipartimento di Scienza dei Materiali, Università di Milano─Bicocca, Via Roberto Cozzi 55, 20125 Milano, Italy
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13
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Barlocco I, Cipriano LA, Di Liberto G, Pacchioni G. Modeling Hydrogen and Oxygen Evolution Reactions on Single Atom Catalysts with Density Functional Theory: Role of the Functional. Advcd Theory and Sims 2022. [DOI: 10.1002/adts.202200513] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Ilaria Barlocco
- Dipartimento di Scienza dei Materiali Università di Milano–Bicocca via R. Cozzi 55 Milano 20125 Italy
| | - Luis A. Cipriano
- Dipartimento di Scienza dei Materiali Università di Milano–Bicocca via R. Cozzi 55 Milano 20125 Italy
| | - Giovanni Di Liberto
- Dipartimento di Scienza dei Materiali Università di Milano–Bicocca via R. Cozzi 55 Milano 20125 Italy
| | - Gianfranco Pacchioni
- Dipartimento di Scienza dei Materiali Università di Milano–Bicocca via R. Cozzi 55 Milano 20125 Italy
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14
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Navarro JJ, Das M, Tosoni S, Landwehr F, Bruce JP, Heyde M, Pacchioni G, Glorius F, Roldan Cuenya B. Covalent Adsorption of N-Heterocyclic Carbenes on a Copper Oxide Surface. J Am Chem Soc 2022; 144:16267-16271. [PMID: 36049156 PMCID: PMC9479068 DOI: 10.1021/jacs.2c06335] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
![]()
Tuning the properties of oxide surfaces through the adsorption
of designed ligands is highly desirable for several applications,
such as catalysis. N-Heterocyclic carbenes (NHCs) have been successfully
employed as ligands for the modification of metallic surfaces. On
the other hand, their potential as modifiers of ubiquitous oxide surfaces
still needs to be developed. Here we show that a model NHC binds covalently
to a copper oxide surface under UHV conditions. In particular, we
report the first example of a covalent bond between NHCs and oxygen
atoms from the oxide layer. This study demonstrates that NHC can also
act as a strong anchor on oxide surfaces.
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Affiliation(s)
- Juan J Navarro
- Department of Interface Science, Fritz-Haber Institute of the Max-Planck Society, 14195 Berlin, Germany
| | - Mowpriya Das
- Westfälische Wilhelms-Universität Münster, Organisch-Chemisches Institut, 48149 Münster, Germany
| | - Sergio Tosoni
- Dipartimento di Scienza dei Materiali, Università di Milano-Bicocca, Via Cozzi 55, 20125 Milano, Italy
| | - Felix Landwehr
- Department of Interface Science, Fritz-Haber Institute of the Max-Planck Society, 14195 Berlin, Germany
| | - Jared P Bruce
- Department of Interface Science, Fritz-Haber Institute of the Max-Planck Society, 14195 Berlin, Germany
| | - Markus Heyde
- Department of Interface Science, Fritz-Haber Institute of the Max-Planck Society, 14195 Berlin, Germany
| | - Gianfranco Pacchioni
- Dipartimento di Scienza dei Materiali, Università di Milano-Bicocca, Via Cozzi 55, 20125 Milano, Italy
| | - Frank Glorius
- Westfälische Wilhelms-Universität Münster, Organisch-Chemisches Institut, 48149 Münster, Germany
| | - Beatriz Roldan Cuenya
- Department of Interface Science, Fritz-Haber Institute of the Max-Planck Society, 14195 Berlin, Germany
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15
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Maleki F, Pacchioni G. Probing the nature of Lewis acid sites on oxide surfaces with 31P(CH 3) 3 NMR: a theoretical analysis. Phys Chem Chem Phys 2022; 24:19773-19782. [PMID: 35972443 DOI: 10.1039/d2cp03306b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The characterization of catalytic oxide surfaces is often done by studying the properties of adsorbed probe molecules. The 31P NMR chemical shift of adsorbed trimethylphosphine, P(CH3)3 or TMP, has been used to identify the presence of different facets in oxide nanocrystals and to study the acid-base properties of the adsorption sites. The NMR studies are often complemented by DFT calculations to provide additional information on TMP adsorption mode, bond strength, etc. So far, however, no systematic study has been undertaken in order to compare on the same footing the chemical shifts and the adsorption properties of TMP on different oxide surfaces. In this work we report the results of DFT+D (D = dispersion) calculations on the adsorption of TMP on the following oxide surfaces: anatase TiO2(101) and (001), rutile TiO2(110), tetragonal ZrO2(101), stepped ZrO2(134) and (145) surfaces, rutile SnO2(110), (101) and (100), wurtzite ZnO(101̄0), and cubic CeO2(111) and (110). Beside the stoichiometric surfaces, also reduced oxides have been considered creating O vacancies in various sites. TMP has been adsorbed on top of variously coordinated Lewis acid cation sites, with the aim to identify, also with the support of machine learning algorithms, trends or patterns that can help to correlate the 31P chemical shift with physico-chemical properties of the oxide surfaces such as adsorption energy, Bader charges, cation-P distance, work function, etc. Some simple correlation can be found within the same oxide between the 31P chemical shift and the adsorption energy, while when the full set of data is considered the only correlation found is with the net charge on the TMP molecule, a descriptor of the acid strength of the adsorption site.
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Affiliation(s)
- Farahnaz Maleki
- Dipartimento di Scienza dei Materiali, Università di Milano-Bicocca, via R. Cozzi 55, 20125 Milano, Italy.
| | - Gianfranco Pacchioni
- Dipartimento di Scienza dei Materiali, Università di Milano-Bicocca, via R. Cozzi 55, 20125 Milano, Italy.
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Das T, Di Liberto G, Pacchioni G. Quantum confinement in chalcogenides 2D nanostructures from first principles. J Phys Condens Matter 2022; 34:405301. [PMID: 35868296 DOI: 10.1088/1361-648x/ac838b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2022] [Accepted: 07/22/2022] [Indexed: 06/15/2023]
Abstract
We investigated the impact of quantum confinement on the band gap of chalcogenides 2D nanostructures by means of density functional theory. We studied six different systems: MoS2, WS2, SnS2, GaS, InSe, and HfS2and we simulated nanosheets of increasing thickness, ranging from ultrathin films to ∼10-13 nm thick slabs, a size where the properties converge to the bulk. In some cases, the convergence of the band gap with slab thickness is rather slow, and sizeable deviations from the bulk value are still present with few nm-thick sheets. The results of the simulations were compared with the available experimental data, finding a quantitative agreement. The impact of quantum confinement can be rationalized in terms of effective masses of electrons and holes and system's size. These results show the possibility of reliably describing quantum confinement effects on systems for which experimental data are not available.
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Affiliation(s)
- Tilak Das
- Dipartimento di Scienza dei Materiali, Università di Milano-Bicocca, via Cozzi 55, Milano, 20125, Italy
| | - Giovanni Di Liberto
- Dipartimento di Scienza dei Materiali, Università di Milano-Bicocca, via Cozzi 55, Milano, 20125, Italy
| | - Gianfranco Pacchioni
- Dipartimento di Scienza dei Materiali, Università di Milano-Bicocca, via Cozzi 55, Milano, 20125, Italy
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Navarro JJ, Das M, Tosoni S, Landwehr F, Koy M, Heyde M, Pacchioni G, Glorius F, Roldan Cuenya B. Growth of N-Heterocyclic Carbene Assemblies on Cu(100) and Cu(111): From Single Molecules to Magic-Number Islands. Angew Chem Int Ed Engl 2022; 61:e202202127. [PMID: 35468246 PMCID: PMC9401596 DOI: 10.1002/anie.202202127] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Indexed: 11/18/2022]
Abstract
N‐Heterocyclic carbenes (NHCs) have superior properties as building blocks of self‐assembled monolayers (SAMs). Understanding the influence of the substrate in the molecular arrangement is a fundamental step before employing these ligands in technological applications. Herein, we study the molecular arrangement of a model NHC on Cu(100) and Cu(111). While mostly disordered phases appear on Cu(100), on Cu(111) well‐defined structures are formed, evolving from magic‐number islands to molecular ribbons with coverage. This work presents the first example of magic‐number islands formed by NHC assemblies on flat surfaces. Diffusion and commensurability are key factors explaining the observed arrangements. These results shed light on the molecule‐substrate interaction and open the possibility of tuning nanopatterned structures based on NHC assemblies.
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Affiliation(s)
- Juan J Navarro
- Fritz-Haber Institute of the Max Planck Society, Department of Interface Science, Faradayweg 4-6, 14195, Berlin, Germany
| | - Mowpriya Das
- Westfälische Wilhelms-Universität, Organisch-Chemisches Institut, Corrensstraße 40, 48149, Münster, Germany
| | - Sergio Tosoni
- Dipartimento di Scienza dei Materiali, Università di Milano-Bicocca, Via Cozzi 55, 20125, Milano, Italy
| | - Felix Landwehr
- Fritz-Haber Institute of the Max Planck Society, Department of Interface Science, Faradayweg 4-6, 14195, Berlin, Germany
| | - Maximilian Koy
- Westfälische Wilhelms-Universität, Organisch-Chemisches Institut, Corrensstraße 40, 48149, Münster, Germany
| | - Markus Heyde
- Fritz-Haber Institute of the Max Planck Society, Department of Interface Science, Faradayweg 4-6, 14195, Berlin, Germany
| | - Gianfranco Pacchioni
- Dipartimento di Scienza dei Materiali, Università di Milano-Bicocca, Via Cozzi 55, 20125, Milano, Italy
| | - Frank Glorius
- Westfälische Wilhelms-Universität, Organisch-Chemisches Institut, Corrensstraße 40, 48149, Münster, Germany
| | - Beatriz Roldan Cuenya
- Fritz-Haber Institute of the Max Planck Society, Department of Interface Science, Faradayweg 4-6, 14195, Berlin, Germany
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Affiliation(s)
- Giovanni Di Liberto
- Università degli Studi di Milano-Bicocca: Universita degli Studi di Milano-Bicocca Dipartimento di Scienza dei Materiali ITALY
| | - Luis Antionio Cipriano
- Università degli Studi di Milano-Bicocca: Universita degli Studi di Milano-Bicocca Dipartimento di Scienza dei Materiali ITALY
| | - Gianfranco Pacchioni
- Università degli Studi di Milano-Bicocca Dipartimento di Scienza dei Materiali U05, Piano: P02, Stanza: 2073Via Roberto Cozzi 55 20125 Milano ITALY
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Tosoni S, Pacchioni G. Magnetic nature and hyperfine interactions of transition metal atoms adsorbed on ultrathin insulating films: a challenge for DFT. Phys Chem Chem Phys 2022; 24:15891-15903. [PMID: 35762384 DOI: 10.1039/d2cp01224c] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The magnetic ground state and the hyperfine coupling parameters of some first-row transition metal (TM) atoms (Ti, Cr, Mn, Fe, Co, and Ni) adsorbed on ultrathin insulating oxide films are studied by means of DFT calculations. The results obtained using GGA, screened hybrid, and GGA+U functionals are compared for TMs adsorbed on free-standing MgO(100). Then, the case of adsorption on MgO mono- and bilayers supported on Ag(100) is studied using GGA+U. Along with the problematic aspects inherent to the calculation of hyperfine coupling constants, a critical dependence on the magnetic state and electron configuration of the TM is reported, which implies a real challenge for the state-of-the-art DFT methods. In the cases where all functionals considered provide a coherent magnetic and electron configuration, however, the calculated hyperfine parameters do not depend significantly on the choice of the functional. In this respect, the role of the metal support in the hyperfine coupling constants is highly system-dependent and becomes crucial in all cases where the support modifies the oxidation state of the adatom, induces a change in the bonding site or simply induces a rearrangement of the orbital energy diagram. This has important implications for the modelling of single TM atoms deposited on insulating ultrathin films supported on metals for application in quantum technologies or as memory devices.
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Affiliation(s)
- Sergio Tosoni
- Dipartimento di Scienza dei Materiali, Università di Milano-Bicocca, Via Roberto Cozzi 55, 20125 Milan, Italy.
| | - Gianfranco Pacchioni
- Dipartimento di Scienza dei Materiali, Università di Milano-Bicocca, Via Roberto Cozzi 55, 20125 Milan, Italy.
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Navarro JJ, Das M, Tosoni S, Landwehr F, Koy M, Heyde M, Pacchioni G, Glorius F, Roldan Cuenya B. Wachstum von N‐heterocyclischen Carbenen auf Cu(100) und Cu(111): von einzelnen Molekülen bis hin zu Inseln mit magischen Zahlen. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202202127] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Juan J. Navarro
- Fritz-Haber-Institut der Max-Planck-Gesellschaft Abteilung für Grenzflächenwissenschaft Faradayweg 4–6 14195 Berlin Deutschland
| | - Mowpriya Das
- Westfälische Wilhelms-Universität Organisch-Chemisches Institut Corrensstraße 40 48149 Münster Deutschland
| | - Sergio Tosoni
- Dipartimento di Scienza dei Materiali Università di Milano-Bicocca Via Cozzi 55 20125 Milano Italien
| | - Felix Landwehr
- Fritz-Haber-Institut der Max-Planck-Gesellschaft Abteilung für Grenzflächenwissenschaft Faradayweg 4–6 14195 Berlin Deutschland
| | - Maximilian Koy
- Westfälische Wilhelms-Universität Organisch-Chemisches Institut Corrensstraße 40 48149 Münster Deutschland
| | - Markus Heyde
- Fritz-Haber-Institut der Max-Planck-Gesellschaft Abteilung für Grenzflächenwissenschaft Faradayweg 4–6 14195 Berlin Deutschland
| | - Gianfranco Pacchioni
- Dipartimento di Scienza dei Materiali Università di Milano-Bicocca Via Cozzi 55 20125 Milano Italien
| | - Frank Glorius
- Westfälische Wilhelms-Universität Organisch-Chemisches Institut Corrensstraße 40 48149 Münster Deutschland
| | - Beatriz Roldan Cuenya
- Fritz-Haber-Institut der Max-Planck-Gesellschaft Abteilung für Grenzflächenwissenschaft Faradayweg 4–6 14195 Berlin Deutschland
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Pacchioni G, Rahman TS. Defect engineering of oxide surfaces: dream or reality? J Phys Condens Matter 2022; 34:291501. [PMID: 35504272 DOI: 10.1088/1361-648x/ac6c6d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Accepted: 05/03/2022] [Indexed: 06/14/2023]
Abstract
In this brief perspective we analyze the present status of the field of defect engineering of oxide surfaces. In particular we discuss the tools and techniques available to generate, identify, quantify, and characterize point defects at oxide surfaces and the main areas where these centers play a role in practical applications.
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Affiliation(s)
- Gianfranco Pacchioni
- Dipartimento di Scienza dei Materiali, Università di Milano-Bicocca, via R. Cozzi 55, 202125, Milano, Italy
| | - Talat S Rahman
- Department of Physics, University of Central Florida, Orlando, FL 32816, United States of America
- Renewable Energy and Chemical Transformation Cluster, University of Central Florida, Orlando, FL 32816, United States of America
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Affiliation(s)
- Giovanni Di Liberto
- Dipartimento di Scienza dei Materiali, Università di Milano - Bicocca, via R. Cozzi 55, 20125 Milano, Italy
| | - Luis A. Cipriano
- Dipartimento di Scienza dei Materiali, Università di Milano - Bicocca, via R. Cozzi 55, 20125 Milano, Italy
| | - Gianfranco Pacchioni
- Dipartimento di Scienza dei Materiali, Università di Milano - Bicocca, via R. Cozzi 55, 20125 Milano, Italy
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Bajada MA, Sanjosé-Orduna J, Di Liberto G, Tosoni S, Pacchioni G, Noël T, Vilé G. Interfacing single-atom catalysis with continuous-flow organic electrosynthesis. Chem Soc Rev 2022; 51:3898-3925. [PMID: 35481480 DOI: 10.1039/d2cs00100d] [Citation(s) in RCA: 24] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The global warming crisis has sparked a series of environmentally cautious trends in chemistry, allowing us to rethink the way we conduct our synthesis, and to incorporate more earth-abundant materials in our catalyst design. "Single-atom catalysis" has recently appeared on the catalytic spectrum, and has truly merged the benefits that homogeneous and heterogeneous analogues have to offer. Further still, the possibility to activate these catalysts by means of a suitable electric potential could pave the way for a true integration of diverse synthetic methodologies and renewable electricity. Despite their esteemed benefits, single-atom electrocatalysts are still limited to the energy sector (hydrogen evolution reaction, oxygen reduction, etc.) and numerous examples in the literature still invoke the use of precious metals (Pd, Pt, Ir, etc.). Additionally, batch electroreactors are employed, which limit the intensification of such processes. It is of paramount importance that the field continues to grow in a more sustainable direction, seeking new ventures into the space of organic electrosynthesis and flow electroreactor technologies. In this piece, we discuss some of the progress being made with earth abundant homogeneous and heterogeneous electrocatalysts and flow electrochemistry, within the context of organic electrosynthesis, and highlight the prospects of alternatively utilizing single-atom catalysts for such applications.
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Affiliation(s)
- Mark A Bajada
- Department of Chemistry, Materials, and Chemical Engineering "Giulio Natta", Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano, Italy.
| | - Jesús Sanjosé-Orduna
- Flow Chemistry Group, van't Hoff Institute for Molecular Sciences, Universiteit van Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
| | - Giovanni Di Liberto
- Department of Materials Science, Università di Milano Bicocca, via R. Cozzi 55, 20125 Milano, Italy
| | - Sergio Tosoni
- Department of Materials Science, Università di Milano Bicocca, via R. Cozzi 55, 20125 Milano, Italy
| | - Gianfranco Pacchioni
- Department of Materials Science, Università di Milano Bicocca, via R. Cozzi 55, 20125 Milano, Italy
| | - Timothy Noël
- Flow Chemistry Group, van't Hoff Institute for Molecular Sciences, Universiteit van Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
| | - Gianvito Vilé
- Department of Chemistry, Materials, and Chemical Engineering "Giulio Natta", Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano, Italy.
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Vilé G, Di Liberto G, Tosoni S, Sivo A, Ruta V, Nachtegaal M, Clark AH, Agnoli S, Zou Y, Savateev A, Antonietti M, Pacchioni G. Azide-Alkyne Click Chemistry over a Heterogeneous Copper-Based Single-Atom Catalyst. ACS Catal 2022. [DOI: 10.1021/acscatal.1c05610] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Gianvito Vilé
- Department of Chemistry, Materials, and Chemical Engineering “Giulio Natta”, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano, Italy
| | - Giovanni Di Liberto
- Department of Materials Science, University of Milano-Bicocca, Via Roberto Cozzi 55, 20125 Milano, Italy
| | - Sergio Tosoni
- Department of Materials Science, University of Milano-Bicocca, Via Roberto Cozzi 55, 20125 Milano, Italy
| | - Alessandra Sivo
- Department of Chemistry, Materials, and Chemical Engineering “Giulio Natta”, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano, Italy
| | - Vincenzo Ruta
- Department of Chemistry, Materials, and Chemical Engineering “Giulio Natta”, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano, Italy
| | - Maarten Nachtegaal
- Paul Scherrer Institute, Forschingsstrasse 111, 5232 Villigen, Switzerland
| | - Adam H. Clark
- Paul Scherrer Institute, Forschingsstrasse 111, 5232 Villigen, Switzerland
| | - Stefano Agnoli
- Department of Chemical Sciences, University of Padova, Via F. Marzolo 1, 35131 Padova, Italy
| | - Yajun Zou
- Department of Colloid Chemistry, Max Planck Institute of Colloids and Interfaces, Potsdam-Golm Science Park, Am Muehlenberg 1 OT, Golm, Potsdam 14476, Germany
| | - Aleksandr Savateev
- Department of Colloid Chemistry, Max Planck Institute of Colloids and Interfaces, Potsdam-Golm Science Park, Am Muehlenberg 1 OT, Golm, Potsdam 14476, Germany
| | - Markus Antonietti
- Department of Colloid Chemistry, Max Planck Institute of Colloids and Interfaces, Potsdam-Golm Science Park, Am Muehlenberg 1 OT, Golm, Potsdam 14476, Germany
| | - Gianfranco Pacchioni
- Department of Materials Science, University of Milano-Bicocca, Via Roberto Cozzi 55, 20125 Milano, Italy
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Pacchioni G. From Li clusters to nanocatalysis: A brief tour of 40 years of cluster chemistry. Inorganica Chim Acta 2022. [DOI: 10.1016/j.ica.2021.120680] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Thang HV, Maleki F, Tosoni S, Pacchioni G. Vibrational Properties of CO Adsorbed on Au Single Atom Catalysts on TiO2(101), ZrO2(101), CeO2(111), and LaFeO3(001) Surfaces: A DFT Study. Top Catal 2021. [DOI: 10.1007/s11244-021-01514-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
AbstractThe nature and local environment of Au single atoms supported and stabilized on four different oxides is studied by means of DFT + U calculations using CO as probe molecule and its stretching frequency, ωe, as a fingerprint of the site where the Au atom is bound. Four oxides are considered, anatase TiO2, tetragonal ZrO2, cubic CeO2, and a perovskite LaFeO3. In this latter case a recently reported experimental study has detected a stretching mode for CO adsorbed on Au1/LaFeO3 of 2215 cm−1, with a large blue shift, ∆ω(CO) = 72 cm−1 with respect to free CO. In order to identify the Au adsorption site that can give rise to this large blue-shift we have considered five cases: (a) Au replacing a lattice cation, (Au)subM; (b) Au replacing a lattice O anion, (Au)subO; (c) Au adsorbed on the surface, (Au)ads; (d) Au bound to an extra O atom on the surface, (AuO)ads, or (e) Au bound to two extra O atoms on the surface, (AuO2)ads. It turns out that the correct reproduction of ∆ω for CO adsorbed on positively charged gold, Auδ+, is challenging for DFT. Therefore, we have performed a comparative study of Auδ+-CO molecular compounds for which ωe(CO) is known experimentally using various kinds of DFT functionals and accurate CCSD and CCSD(T) quantum chemistry methods. Also based on this comparison we propose a tentative assignment for the observed frequency of CO adsorbed on Au1/LaFeO3 single atom catalyst.
Graphic Abstract
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Di Liberto G, Cipriano LA, Pacchioni G. Role of Dihydride and Dihydrogen Complexes in Hydrogen Evolution Reaction on Single-Atom Catalysts. J Am Chem Soc 2021; 143:20431-20441. [PMID: 34821146 PMCID: PMC8662730 DOI: 10.1021/jacs.1c10470] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Indexed: 11/30/2022]
Abstract
The hydrogen evolution reaction (HER) has a key role in electrochemical water splitting. Recently a lot of attention has been dedicated to HER from single atom catalysts (SACs). The activity of SACs in HER is usually rationalized or predicted using the original model proposed by Nørskov where the free energy of a H atom adsorbed on an extended metal surface M (formation of an MH intermediate) is used to explain the trends in the exchange current for HER. However, SACs differ substantially from metal surfaces and can be considered analogues of coordination compounds. In coordination chemistry, at variance with metal surfaces, stable dihydride or dihydrogen complexes (HMH) can form. We show that the same can occur on SACs and that the formation of stable HMH intermediates, in addition to the MH one, may change the kinetics of the process. Extending the original kinetic model to the case of two intermediates (MH and HMH), one obtains a three-dimensional volcano plot for the HER on SACs. DFT numerical simulations on 55 models demonstrate that the new kinetic model may lead to completely different conclusions about the activity of SACs in HER. The results are validated against selected experimental cases. The work provides an example of the important analogies between the chemistry of SACs and that of coordination compounds.
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Affiliation(s)
| | - Luis A. Cipriano
- Dipartimento di Scienza dei
Materiali, Università di Milano-Bicocca, Via R. Cozzi 55, 20125 Milano, Italy
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Tosoni S, Di Liberto G, Pacchioni G. Structures and properties of Pd nanoparticles intercalated in layered TiO2: A computational study. Catal Today 2021. [DOI: 10.1016/j.cattod.2021.07.030] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Tan H, Shan G, Pacchioni G. Prediction of 2D ferromagnetism and monovalent europium ions in EuBr/graphene heterojunctions. Phys Chem Chem Phys 2021; 23:25500-25506. [PMID: 34730141 DOI: 10.1039/d1cp02218k] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Europium, one of the rare-earth elements, exhibits +2 and +3 valence states and has been widely used for the magnetic modification of materials. Based on density functional theory calculations, we predicted 2D EuBr/graphene heterojunctions to exhibit metallicity, huge intrinsic-ferromagnetism nearly 7.0 μB per Eu and the special monovalent Eu ions. Electron localization function (ELF), difference charge densities and Bader charge analyses demonstrated that there are cation-π interactions between the EuBr films and graphene. Graphene works as a substrate to enable the stability of EuBr monolayer crystals, where EuBr plays an important role to yield ferromagnetism and enhance metallicity in the heterojunctions. Monte Carlo simulations were used to estimate a Curie temperature of about 7 K, which, together with magnetic configurations, can be further modulated by external strains and charge-carrier doping. In general, our theoretical work predicts the properties of novel 2D ferromagnetic EuBr/graphene heterojunctions, suggesting the possibility of combining 2D intrinsic-ferromagnetic metal halide crystals and graphene, and opening up a new perspective in next-generation electronic, spintronic devices and high-performance sensors.
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Affiliation(s)
- Haoyi Tan
- School of Instrumentation Science and Opto-electronics Engineering & Institute of Precision Instrument and Quantum Sensing, Beihang University, Beijing 100191, China.
| | - Guangcun Shan
- School of Instrumentation Science and Opto-electronics Engineering & Institute of Precision Instrument and Quantum Sensing, Beihang University, Beijing 100191, China. .,Department of Materials Science and Engineering, City University of Hong Kong, Kowloon Tong, Hong Kong SAR
| | - Gianfranco Pacchioni
- Dipartimento di Scienza dei Materiali, Università degli Studi Milano-Bicocca, 20125 Milano, Italy
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Maleki F, Pacchioni G. Iso-valent doping of reducible oxides: a comparison of rutile (110) and anatase (101) TiO 2surfaces. J Phys Condens Matter 2021; 33:494001. [PMID: 34521076 DOI: 10.1088/1361-648x/ac268e] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Accepted: 09/14/2021] [Indexed: 06/13/2023]
Abstract
We studied the role of iso-valent heteroatoms replacing Ti4+cations in the lattice of two titania polymorphs, rutile (r-) and anatase (a-) by means of first principles calculations. The r-TiO2(110) and the a-TiO2(101) surfaces have been considered and Ti ions in the bulk, sub-surface, and surface sites have been replaced with Si, Ge, Sn, Pb, Zr, Hf, and Ce ions: surface or sub-surface sites are clearly preferred. Since the dopants have the same number of valence electrons as the replaced Ti atom, they can have only two effects: one is steric, related to the different size of the dopant compared to Ti4+; the other is an orbital effect, due to the energy levels associated to the dopant not present on the pristine surface. Both these effects can modify locally the geometric and electronic structure of the surface, in particular by introducing new states in the band gap. To check the effect of the dopants on the surface reactivity we studied as an example the decomposition of HCOOH which can follow four different paths with desorption of (a) H2,(b) CO, (c) H2O, or (d) CO2. The results show the very different behavior of the two titania polymorphs considered, rutile and anatase: rutile is more reactive and more easily reduced than anatase. For specular reasons, the presence of the dopants has in general more pronounced effects on anatase, as they can deeply modify the surface reactivity and the HCOOH decomposition path.
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Affiliation(s)
- Farahnaz Maleki
- Dipartimento di Scienza dei Materiali, Università di Milano-Bicocca, via R. Cozzi 55, 20125 Milano, Italy
| | - Gianfranco Pacchioni
- Dipartimento di Scienza dei Materiali, Università di Milano-Bicocca, via R. Cozzi 55, 20125 Milano, Italy
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Di Liberto G, Cipriano LA, Tosoni S, Pacchioni G. Frontispiece: Rational Design of Semiconductor Heterojunctions for Photocatalysis. Chemistry 2021. [DOI: 10.1002/chem.202185362] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Giovanni Di Liberto
- Dipartimento di Scienza dei Materiali Università di Milano – Bicocca Via R. Cozzi 55 20125 Milano Italy
| | - Luis A. Cipriano
- Dipartimento di Scienza dei Materiali Università di Milano – Bicocca Via R. Cozzi 55 20125 Milano Italy
| | - Sergio Tosoni
- Dipartimento di Scienza dei Materiali Università di Milano – Bicocca Via R. Cozzi 55 20125 Milano Italy
| | - Gianfranco Pacchioni
- Dipartimento di Scienza dei Materiali Università di Milano – Bicocca Via R. Cozzi 55 20125 Milano Italy
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Abstract
Electronic structure calculations provide a useful complement to experimental characterization tools in the atomic-scale design of semiconductor heterojunctions for photocatalysis. The band alignment of the heterojunction is of fundamental importance to achieve an efficient charge carrier separation, so as to reduce electron/hole recombination and improve photoactivity. The accurate prediction of the offsets of valence and conduction bands in the constituent units is thus of key importance but poses several methodological and practical problems. In this Minireview we address some of these problems by considering selected examples of binary and ternary semiconductor heterojunctions and how these are determined at the level of density functional theory (DFT). The atomically precise description of the interface, the consequent charge polarization, the role of quantum confinement, the possibility to use facet engineering to determine a specific band alignment, are among the effects discussed, with particular attention to pros and cons of each one of these aspects. This analysis shows the increasingly important role of accurate electronic structure calculations to drive the design and the preparation of new interfaces with desired properties.
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Affiliation(s)
- Giovanni Di Liberto
- Dipartimento di Scienza dei MaterialiUniversità di Milano – BicoccaVia R. Cozzi 5520125MilanoItaly
| | - Luis A. Cipriano
- Dipartimento di Scienza dei MaterialiUniversità di Milano – BicoccaVia R. Cozzi 5520125MilanoItaly
| | - Sergio Tosoni
- Dipartimento di Scienza dei MaterialiUniversità di Milano – BicoccaVia R. Cozzi 5520125MilanoItaly
| | - Gianfranco Pacchioni
- Dipartimento di Scienza dei MaterialiUniversità di Milano – BicoccaVia R. Cozzi 5520125MilanoItaly
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Yim CM, Lamoureux PS, Mellor A, Pang CL, Idriss H, Pacchioni G, Thornton G. Size and Shape Dependence of the Electronic Structure of Gold Nanoclusters on TiO 2. J Phys Chem Lett 2021; 12:8363-8369. [PMID: 34432476 DOI: 10.1021/acs.jpclett.1c02167] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Understanding the mechanism behind the superior catalytic power of single- or few-atom heterogeneous catalysts has become an important topic in surface chemistry. This is particularly the case for gold, with TiO2 being an efficient support. Here we use scanning tunneling microscopy/spectroscopy with theoretical calculations to investigate the adsorption geometry and local electronic structure of several-atom Au clusters on rutile TiO2(110), with the clusters fabricated by controlled manipulation of single atoms. Our study confirms that Au1 and Au2 clusters prefer adsorption at surface O vacancies. Au3 clusters adsorb at O vacancies in a linear-chain configuration parallel to the surface; in the absence of O vacancies they adsorb at Ti5c sites with a structure of a vertically pointing upright triangle. We find that both the electronic structure and cluster-substrate charge transfer depend critically on the cluster size, bonding configuration, and local environment. This suggests the possibility of engineering cluster selectivity for specific catalytic reactions.
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Affiliation(s)
- Chi-Ming Yim
- Department of Chemistry and London Centre for Nanotechnology, University College London, 20 Gordon Street, London WC1H 0AJ, U.K
| | - Philomena Schlexer Lamoureux
- Dipartimento di Scienza dei Materiali, Università degli Studi Milano-Bicocca, via R. Cozzi 55, 20126 Milano, Italy
| | - Andrew Mellor
- Department of Chemistry and London Centre for Nanotechnology, University College London, 20 Gordon Street, London WC1H 0AJ, U.K
| | - Chi L Pang
- Department of Chemistry and London Centre for Nanotechnology, University College London, 20 Gordon Street, London WC1H 0AJ, U.K
| | - Hicham Idriss
- Surface Science and Advanced Characterisation, Chemical Sciences Division, SABIC-CRD at KAUST, Thuwal 23955, Saudi Arabia
| | - Gianfranco Pacchioni
- Dipartimento di Scienza dei Materiali, Università degli Studi Milano-Bicocca, via R. Cozzi 55, 20126 Milano, Italy
| | - Geoff Thornton
- Department of Chemistry and London Centre for Nanotechnology, University College London, 20 Gordon Street, London WC1H 0AJ, U.K
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Grigioni I, Di Liberto G, Dozzi MV, Tosoni S, Pacchioni G, Selli E. WO 3/BiVO 4 Photoanodes: Facets Matching at the Heterojunction and BiVO 4 Layer Thickness Effects. ACS Appl Energy Mater 2021; 4:8421-8431. [PMID: 34485843 PMCID: PMC8414527 DOI: 10.1021/acsaem.1c01623] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Accepted: 07/30/2021] [Indexed: 05/31/2023]
Abstract
Photoelectrochemical solar energy conversion offers a way to directly store light into energy-rich chemicals. Photoanodes based on the WO3/BiVO4 heterojunction are most effective mainly thanks to the efficient separation of photogenerated charges. The WO3/BiVO4 interfacial space region in the heterojunction is investigated here with the increasing thickness of the BiVO4 layer over a WO3 scaffold. On the basis of X-ray diffraction analysis results, density functional theory simulations show a BiVO4 growth over the WO3 layer along the BiVO4 {010} face, driven by the formation of a stable interface with new covalent bonds, with a favorable band alignment and band bending between the two oxides. This crystal facet phase matching allows a smooth transition between the electronic states of the two oxides and may be a key factor ensuring the high efficiency attained with this heterojunction. The photoelectrochemical activity of the WO3/BiVO4 photoanodes depends on both the irradiation wavelength and the thickness of the visible-light-absorbing BiVO4 layer, a 75 nm thick BiVO4 layer on WO3 being best performing.
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Affiliation(s)
- Ivan Grigioni
- Dipartimento
di Chimica, Università degli Studi
di Milano, Via Golgi
19, 20133 Milano, Italy
| | - Giovanni Di Liberto
- Dipartimento
di Scienza dei Materiali, Università
di Milano-Bicocca, Via
Cozzi 55, 20125 Milano, Italy
| | - Maria Vittoria Dozzi
- Dipartimento
di Chimica, Università degli Studi
di Milano, Via Golgi
19, 20133 Milano, Italy
| | - Sergio Tosoni
- Dipartimento
di Scienza dei Materiali, Università
di Milano-Bicocca, Via
Cozzi 55, 20125 Milano, Italy
| | - Gianfranco Pacchioni
- Dipartimento
di Scienza dei Materiali, Università
di Milano-Bicocca, Via
Cozzi 55, 20125 Milano, Italy
| | - Elena Selli
- Dipartimento
di Chimica, Università degli Studi
di Milano, Via Golgi
19, 20133 Milano, Italy
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Di Liberto G, Pacchioni G. Band offset in semiconductor heterojunctions. J Phys Condens Matter 2021; 33:415002. [PMID: 34284370 DOI: 10.1088/1361-648x/ac1620] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Accepted: 07/20/2021] [Indexed: 06/13/2023]
Abstract
Semiconductor heterojunctions are widely applied in solid-state device applications, including semiconductor lasers, solar cells, and transistors. In photocatalysis they are of interest due to their capability to hinder charge carriers' recombination. A key role in the performance of heterojunctions is that of the alignment of the band edges of the two units composing the junction. In this work, we compare the performances of three widely applied approaches for the simulation of semiconductors heterostructures, based on density functional theory calculations with hybrid functionals. We benchmark the band offsets of ten semiconductors heterostructures for which experimental values are available: AlP/GaP, AlP/Si, AlAs/GaAs, AlAs/Ge, GaAs/Ge, GaP/Si, ZnSe/Ge, ZnSe/AlAs, ZnSe/GaAs, and TiO2/SrTiO3. The methods considered are (i) the alternating slabs junction (ASJ), (ii) the surface terminated junction (STJ), and (iii) the independent units (IU) approach. Moreover, two different ways to determine a common reference have been considered, (i) the plane averaged electrostatic potential, and (ii) the energy of the core levels. Advantages, drawbacks and overall performances of each method are discussed. The results suggest that the accuracy in the estimation of the band offsets is ∼0.2 eV when the ASJ method is applied. The STJ approach provides a similar accuracy, while the neglection of any interface effect, as in the IU method, provides only a qualitative estimate of the band offset and can result in significant deviations from the experiment.
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Affiliation(s)
- Giovanni Di Liberto
- Dipartimento di Scienza dei Materiali, Università di Milano-Bicocca, via R. Cozzi 55, 20125 Milano, Italy
| | - Gianfranco Pacchioni
- Dipartimento di Scienza dei Materiali, Università di Milano-Bicocca, via R. Cozzi 55, 20125 Milano, Italy
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36
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Kaiser S, Maleki F, Zhang K, Harbich W, Heiz U, Tosoni S, Lechner BAJ, Pacchioni G, Esch F. Cluster Catalysis with Lattice Oxygen: Tracing Oxygen Transport from a Magnetite (001) Support onto Small Pt Clusters. ACS Catal 2021. [DOI: 10.1021/acscatal.1c01451] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Affiliation(s)
- Sebastian Kaiser
- Chair of Physical Chemistry, Department of Chemistry, Technical University of Munich, Lichtenbergstr. 4, 85748 Garching, Germany
- Catalysis Research Center, Technical University of Munich, Lichtenbergstr. 4, 85748 Garching, Germany
| | - Farahnaz Maleki
- Dipartimento di Scienza dei Materiali, University of Milano-Bicocca, via Roberto Cozzi 55, 20125 Milano, Italy
| | - Ke Zhang
- Chair of Physical Chemistry, Department of Chemistry, Technical University of Munich, Lichtenbergstr. 4, 85748 Garching, Germany
- Catalysis Research Center, Technical University of Munich, Lichtenbergstr. 4, 85748 Garching, Germany
| | - Wolfgang Harbich
- Institute of Physics, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
| | - Ueli Heiz
- Chair of Physical Chemistry, Department of Chemistry, Technical University of Munich, Lichtenbergstr. 4, 85748 Garching, Germany
- Catalysis Research Center, Technical University of Munich, Lichtenbergstr. 4, 85748 Garching, Germany
| | - Sergio Tosoni
- Dipartimento di Scienza dei Materiali, University of Milano-Bicocca, via Roberto Cozzi 55, 20125 Milano, Italy
| | - Barbara A. J. Lechner
- Chair of Physical Chemistry, Department of Chemistry, Technical University of Munich, Lichtenbergstr. 4, 85748 Garching, Germany
| | - Gianfranco Pacchioni
- Dipartimento di Scienza dei Materiali, University of Milano-Bicocca, via Roberto Cozzi 55, 20125 Milano, Italy
| | - Friedrich Esch
- Chair of Physical Chemistry, Department of Chemistry, Technical University of Munich, Lichtenbergstr. 4, 85748 Garching, Germany
- Catalysis Research Center, Technical University of Munich, Lichtenbergstr. 4, 85748 Garching, Germany
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Büchner C, Eder SD, Nesse T, Kuhness D, Schlexer P, Pacchioni G, Manson JR, Heyde M, Holst B, Freund HJ. Erratum: Bending Rigidity of 2D Silica [Phys. Rev. Lett. 120, 226101 (2018)]. Phys Rev Lett 2021; 127:029902. [PMID: 34296934 DOI: 10.1103/physrevlett.127.029902] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Indexed: 06/13/2023]
Abstract
This corrects the article DOI: 10.1103/PhysRevLett.120.226101.
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Das T, Tosoni S, Pacchioni G. Role of support in tuning the properties of single atom catalysts: Cu, Ag, Au, Ni, Pd, and Pt adsorption on SiO 2/Ru, SiO 2/Pt, and SiO 2/Si ultrathin films. J Chem Phys 2021; 154:134706. [PMID: 33832274 DOI: 10.1063/5.0048104] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
The role of the support in tuning the properties of transition metal (TM) atoms is studied by means of density functional theory calculations. We have considered the adsorption of Cu, Ag, Au, Ni, Pd, and Pt atoms on crystalline silica bilayers, either free-standing or supported on Ru(0001) and Pt(111) metal surfaces. These systems have been compared with an hydroxylated SiO2/Si(100) film simulating the native oxide formed on a silicon wafer. The properties of the TM atoms change significantly on the various supports. While the unsupported silica bilayer weakly binds some of the TM atoms studied, the SiO2/Ru(0001) or SiO2/Pt(111) supports exhibit enhanced reactivity, sometimes resulting in a net electron transfer with the formation of charged species. Differences in the behavior of SiO2/Ru(0001) and SiO2/Pt(111) are rationalized in terms of different work functions and metal/oxide interfacial distances. No electron transfer is observed on the SiO2/Si(100) films. Here, the presence of hydroxyl groups on the surface provides relatively strong binding sites for the TM atoms that can be stabilized by the interaction with one or two OH groups. The final aspect that has been investigated is the porosity of the silica bilayer, at variance with the dense SiO2/Si(100) film. Depending on the atomic size, some TM atoms can penetrate spontaneously through the six-membered silica rings and become stabilized in the pores of the bilayer or at the SiO2/metal interface. This study shows how very different chemical properties can be obtained by depositing the same TM atom on different silica supports.
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Affiliation(s)
- Tilak Das
- Dipartimento di Scienza dei Materiali, Università degli Studi Milano-Bicocca, via R. Cozzi, 55-20125 Milano, Italy
| | - Sergio Tosoni
- Dipartimento di Scienza dei Materiali, Università degli Studi Milano-Bicocca, via R. Cozzi, 55-20125 Milano, Italy
| | - Gianfranco Pacchioni
- Dipartimento di Scienza dei Materiali, Università degli Studi Milano-Bicocca, via R. Cozzi, 55-20125 Milano, Italy
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Di Liberto G, Tosoni S, Pacchioni G. Role of surface termination in forming type-II photocatalyst heterojunctions: the case of TiO 2/BiVO 4. J Phys Condens Matter 2021; 33:075001. [PMID: 33086209 DOI: 10.1088/1361-648x/abc357] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
In this work we investigate TiO2 and BiVO4 nanostructures by means of density functional theory (DFT) calculations, to provide an estimate of the band alignment in TiO2/BiVO4 interfaces, highly active in photo-electrochemistry and photocatalytic water splitting. Calculations were carried out with both DFT range separated and self-consistent dielectric dependent hybrid functionals (HSE06 and PBE0DD). The impact of systems' size has been investigated. The converged electronic levels of TiO2 and BiVO4 surfaces have been used to predict the band alignment in TiO2/BiVO4 heterostructures. Results indicated that when TiO2 (101) surface is matched with BiVO4 (110), a type-II alignment is obtained, where the band edges of BiVO4 are higher in energy that those of TiO2. This picture is favorable for charge-carriers separation upon photoexcitation, where electrons move toward TiO2 and holes toward BiVO4. On the contrary, if TiO2 (101) is interfaced to BiVO4 (010) the offset between the band edges is negligible, thus reducing the driving force toward separation of charge carriers. These results rationalize the dependence on the facet's exposure of the observed photocatalytic performances of TiO2/BiVO4 composites, where the TiO2 (101)/BiVO4 (110) interface outperforms the TiO2 (101)/BiVO4 (010) one.
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Affiliation(s)
- Giovanni Di Liberto
- Dipartimento di Scienza dei Materiali, Università di Milano-Bicocca, via R Cozzi 55, 20125 Milano, Italy
| | - Sergio Tosoni
- Dipartimento di Scienza dei Materiali, Università di Milano-Bicocca, via R Cozzi 55, 20125 Milano, Italy
| | - Gianfranco Pacchioni
- Dipartimento di Scienza dei Materiali, Università di Milano-Bicocca, via R Cozzi 55, 20125 Milano, Italy
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Lewandowski AL, Tosoni S, Gura L, Yang Z, Fuhrich A, Prieto MJ, Schmidt T, Usvyat D, Schneider W, Heyde M, Pacchioni G, Freund H. Frontispiece: Growth and Atomic‐Scale Characterization of Ultrathin Silica and Germania Films: The Crucial Role of the Metal Support. Chemistry 2021. [DOI: 10.1002/chem.202180661] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
| | - Sergio Tosoni
- Department of Materials Science Universitá di Milano-Bicocca Via R. Cozzi, 55 20125 Milan Italy
| | - Leonard Gura
- Fritz-Haber-Institut der Max-Planck-Gesellschaft Faradayweg 4–6 14195 Berlin Germany
| | - Zechao Yang
- Fritz-Haber-Institut der Max-Planck-Gesellschaft Faradayweg 4–6 14195 Berlin Germany
| | - Alexander Fuhrich
- Fritz-Haber-Institut der Max-Planck-Gesellschaft Faradayweg 4–6 14195 Berlin Germany
| | - Mauricio J. Prieto
- Fritz-Haber-Institut der Max-Planck-Gesellschaft Faradayweg 4–6 14195 Berlin Germany
| | - Thomas Schmidt
- Fritz-Haber-Institut der Max-Planck-Gesellschaft Faradayweg 4–6 14195 Berlin Germany
| | - Denis Usvyat
- Institut für Chemie Humboldt-Universität zu Berlin Brook-Taylor-Str. 2 12489 Berlin Germany
| | - Wolf‐Dieter Schneider
- Fritz-Haber-Institut der Max-Planck-Gesellschaft Faradayweg 4–6 14195 Berlin Germany
| | - Markus Heyde
- Fritz-Haber-Institut der Max-Planck-Gesellschaft Faradayweg 4–6 14195 Berlin Germany
| | - Gianfranco Pacchioni
- Department of Materials Science Universitá di Milano-Bicocca Via R. Cozzi, 55 20125 Milan Italy
| | - Hans‐Joachim Freund
- Fritz-Haber-Institut der Max-Planck-Gesellschaft Faradayweg 4–6 14195 Berlin Germany
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41
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Lewandowski AL, Tosoni S, Gura L, Yang Z, Fuhrich A, Prieto MJ, Schmidt T, Usvyat D, Schneider W, Heyde M, Pacchioni G, Freund H. Growth and Atomic-Scale Characterization of Ultrathin Silica and Germania Films: The Crucial Role of the Metal Support. Chemistry 2021; 27:1870-1885. [PMID: 33118653 PMCID: PMC7898484 DOI: 10.1002/chem.202001806] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Revised: 07/06/2020] [Indexed: 11/12/2022]
Abstract
The present review reports on the preparation and atomic-scale characterization of the thinnest possible films of the glass-forming materials silica and germania. To this end state-of-the-art surface science techniques, in particular scanning probe microscopy, and density functional theory calculations have been employed. The investigated films range from monolayer to bilayer coverage where both, the crystalline and the amorphous films, contain characteristic XO4 (X=Si,Ge) building blocks. A side-by-side comparison of silica and germania monolayer, zigzag phase and bilayer films supported on Mo(112), Ru(0001), Pt(111), and Au(111) leads to a more general comprehension of the network structure of glass former materials. This allows us to understand the crucial role of the metal support for the pathway from crystalline to amorphous ultrathin film growth.
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Affiliation(s)
| | - Sergio Tosoni
- Department of Materials ScienceUniversitá di Milano-BicoccaVia R. Cozzi, 5520125MilanItaly
| | - Leonard Gura
- Fritz-Haber-Institut der Max-Planck-GesellschaftFaradayweg 4–614195BerlinGermany
| | - Zechao Yang
- Fritz-Haber-Institut der Max-Planck-GesellschaftFaradayweg 4–614195BerlinGermany
| | - Alexander Fuhrich
- Fritz-Haber-Institut der Max-Planck-GesellschaftFaradayweg 4–614195BerlinGermany
| | - Mauricio J. Prieto
- Fritz-Haber-Institut der Max-Planck-GesellschaftFaradayweg 4–614195BerlinGermany
| | - Thomas Schmidt
- Fritz-Haber-Institut der Max-Planck-GesellschaftFaradayweg 4–614195BerlinGermany
| | - Denis Usvyat
- Institut für ChemieHumboldt-Universität zu BerlinBrook-Taylor-Str. 212489BerlinGermany
| | | | - Markus Heyde
- Fritz-Haber-Institut der Max-Planck-GesellschaftFaradayweg 4–614195BerlinGermany
| | - Gianfranco Pacchioni
- Department of Materials ScienceUniversitá di Milano-BicoccaVia R. Cozzi, 5520125MilanItaly
| | - Hans‐Joachim Freund
- Fritz-Haber-Institut der Max-Planck-GesellschaftFaradayweg 4–614195BerlinGermany
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Di Liberto G, Fatale O, Pacchioni G. Role of surface termination and quantum size in α-CsPbX3 (X = Cl, Br, I) 2D nanostructures for solar light harvesting. Phys Chem Chem Phys 2021; 23:3031-3040. [DOI: 10.1039/d0cp06245f] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Quantum confinement of CsPbBr3 nanoplatelets.
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Affiliation(s)
- Giovanni Di Liberto
- Dipartimento di Scienza dei Materiali
- Università di Milano – Bicocca
- 20125 Milano
- Italy
| | - Ornella Fatale
- Dipartimento di Scienza dei Materiali
- Università di Milano – Bicocca
- 20125 Milano
- Italy
- Università di Pisa
| | - Gianfranco Pacchioni
- Dipartimento di Scienza dei Materiali
- Università di Milano – Bicocca
- 20125 Milano
- Italy
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Abstract
Band alignment and interface polarization of g-C3N4/TiO2 and g-C3N4/SrTiO3/TiO2 interfaces.
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Affiliation(s)
- Giovanni Di Liberto
- Dipartimento di Scienza dei Materiali
- Università di Milano – Bicocca
- 20125 Milano
- Italy
| | - Sergio Tosoni
- Dipartimento di Scienza dei Materiali
- Università di Milano – Bicocca
- 20125 Milano
- Italy
| | - Gianfranco Pacchioni
- Dipartimento di Scienza dei Materiali
- Università di Milano – Bicocca
- 20125 Milano
- Italy
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Affiliation(s)
- Farahnaz Maleki
- Dipartimento di Scienza dei Materiali, Universitá di Milano-Bicocca, via R. Cozzi 55, 20125 Milano, Italy
| | - Gianfranco Pacchioni
- Dipartimento di Scienza dei Materiali, Universitá di Milano-Bicocca, via R. Cozzi 55, 20125 Milano, Italy
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Yu X, Roth JP, Wang J, Sauter E, Nefedov A, Heißler S, Pacchioni G, Wang Y, Wöll C. Chemical Reactivity of Supported ZnO Clusters: Undercoordinated Zinc and Oxygen Atoms as Active Sites. Chemphyschem 2020; 21:2553-2564. [PMID: 33118300 PMCID: PMC7756222 DOI: 10.1002/cphc.202000747] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2020] [Revised: 10/21/2020] [Indexed: 11/06/2022]
Abstract
The growth of ZnO clusters supported by ZnO-bilayers on Ag(111) and the interaction of these oxide nanostructures with water have been studied by a multi-technique approach combining temperature-dependent infrared reflection absorption spectroscopy (IRRAS), grazing-emission X-ray photoelectron spectroscopy, and density functional theory calculations. Our results reveal that the ZnO bilayers exhibiting graphite-like structure are chemically inactive for water dissociation, whereas small ZnO clusters formed on top of these well-defined, yet chemically passive supports show extremely high reactivity - water is dissociated without an apparent activation barrier. Systematic isotopic substitution experiments using H2 16 O/D2 16 O/D2 18 O allow identification of various types of acidic hydroxyl groups. We demonstrate that a reliable characterization of these OH-species is possible via co-adsorption of CO, which leads to a red shift of the OD frequency due to the weak interaction via hydrogen bonding. The theoretical results provide atomic-level insight into the surface structure and chemical activity of the supported ZnO clusters and allow identification of the presence of under-coordinated Zn and O atoms at the edges and corners of the ZnO clusters as the active sites for H2 O dissociation.
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Affiliation(s)
- Xiaojuan Yu
- Institute of Functional InterfacesKarlsruhe Institute of TechnologyEggenstein-Leopoldshafen76344Germany
| | - Jannik P. Roth
- Dipartimento di Scienza dei MaterialiUniversità Milano-BicoccaVia R. Cozzi 5520125MilanoItaly
| | - Junjun Wang
- Institute of Functional InterfacesKarlsruhe Institute of TechnologyEggenstein-Leopoldshafen76344Germany
| | - Eric Sauter
- Institute of Functional InterfacesKarlsruhe Institute of TechnologyEggenstein-Leopoldshafen76344Germany
| | - Alexei Nefedov
- Institute of Functional InterfacesKarlsruhe Institute of TechnologyEggenstein-Leopoldshafen76344Germany
| | - Stefan Heißler
- Institute of Functional InterfacesKarlsruhe Institute of TechnologyEggenstein-Leopoldshafen76344Germany
| | - Gianfranco Pacchioni
- Dipartimento di Scienza dei MaterialiUniversità Milano-BicoccaVia R. Cozzi 5520125MilanoItaly
| | - Yuemin Wang
- Institute of Functional InterfacesKarlsruhe Institute of TechnologyEggenstein-Leopoldshafen76344Germany
| | - Christof Wöll
- Institute of Functional InterfacesKarlsruhe Institute of TechnologyEggenstein-Leopoldshafen76344Germany
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Cipriano LA, Di Liberto G, Tosoni S, Pacchioni G. Quantum confinement in group III-V semiconductor 2D nanostructures. Nanoscale 2020; 12:17494-17501. [PMID: 32808618 DOI: 10.1039/d0nr03577g] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
In this work we investigate the role of quantum confinement in group III-V semiconductor thin films (2D nanostructures). To this end we have studied the electronic structure of nine materials (AlP, AlAs, AlSb, GaP, GaAs, GaSb, InP, InAs and InSb) by means of Density Functional Theory (DFT) calculations using a screened hybrid functional (HSE06). We focus on the structural and electronic properties of bulk and the (110) surfaces, for which we evaluate and rationalize the impact of system size to the band gap and band edge positions. Our results indicate that when the quantum confinement is strong, it mainly affects the position of the Conduction Band Minimum (CBM) of the semiconductor, while the Valence Band Maximum (VBM) is almost insensitive to the system size. The results can be rationalized in terms of electron and hole effective masses. Our conclusions, based on slabs, can be generalized to other cases of quantum confinement such as quantum dots, overcoming the need for an explicit consideration and calculation of the properties of semiconductor nanoparticles.
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Affiliation(s)
- Luis A Cipriano
- Dipartimento di Scienza dei Materiali, Università di Milano - Bicocca, via R. Cozzi 55, 20125 Milano, Italy.
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Maleki F, Pacchioni G. Characterization of Acid and Basic Sites on Zirconia Surfaces and Nanoparticles by Adsorbed Probe Molecules: A Theoretical Study. Top Catal 2020. [DOI: 10.1007/s11244-020-01328-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
AbstractAcid and basic sites on monoclinic and tetragonal zirconia were investigated at the DFT level by computing IR and NMR properties of adsorbed probe molecules. Regular and stepped ZrO2 surfaces as well as stoichiometric zirconia nanoparticles have been considered. Acidity and basicity were probed by the adsorption of carbon monoxide and pyrrole, respectively. CO adsorption shows a positive shift of the C–O stretching frequency in IR spectra while the C atom of CO is shielded and 13C chemical shifts moves to higher field as a function of the strength of the acid site. For the study of basic sites we used a pyrrole molecule, but the interaction between the pyrrole ring and the surface leads to adsorption modes that cannot be used to titrate the surface basicity. On the other hand, at high coverage the molecule assumes an upright position and the formation of a hydrogen bond of the pyrrole NH group with the oxygen atoms of the surfaces provides a proxy of the basic properties of these sites. In particular, we focus on changes of the N–H IR frequency, 1H, 15N, and 17O NMR chemical shifts and their correlations with the surface basicity. Among the correlations found, that between the N–H stretching frequency of adsorbed pyrrole and the 17O NMR chemical shift of the O ion where the molecule is bound show a nice linear correlation. These two properties can provide useful information about the basic character of various O sites on the surface of zirconia.
Graphic Abstract
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Cipriano LA, Di Liberto G, Tosoni S, Pacchioni G. Band Gap in Magnetic Insulators from a Charge Transition Level Approach. J Chem Theory Comput 2020; 16:3786-3798. [PMID: 32427487 PMCID: PMC8007096 DOI: 10.1021/acs.jctc.0c00134] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Indexed: 11/30/2022]
Abstract
The theoretical description of the electronic structure of magnetic insulators and, in particular, of transition-metal oxides (TMOs), MnO, FeO, CoO, NiO, and CuO, poses several problems due to their highly correlated nature. Particularly challenging is the determination of the band gap. The most widely used approach is based on density functional theory (DFT) Kohn-Sham energy levels using self-interaction-corrected functionals (such as hybrid functionals). Here, we present a different approach based on the assumption that the band gap in some TMOs can have a partial Mott-Hubbard character and can be defined as the energy associated with the process Mm+(3dn) + Mm+(3dn) → M(m+1)+(3dn-1) + M(m-1)+(3dn+1). The band gap is thus associated with the removal (ionization potential, I) and addition (electron affinity, A) of one electron to an ion of the lattice. In fact, due to the hybridization of metal with ligand orbitals, these energy contributions are not purely atomic in nature. I and A can be computed accurately using the charge transition level (CTL) scheme. This procedure is based on the calculation of energy levels of charged states and goes beyond the approximations inherent to the Kohn-Sham (KS) approach. The novel and relevant aspect of this work is the extension of CTLs from the domain of point defects to a bulk property such as the band gap. The results show that the calculation based on CTLs provides band gaps in better agreement with experiments than the KS approach, with direct insight into the nature of the gap in these complex systems.
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Affiliation(s)
- Luis A. Cipriano
- Dipartimento di Scienza dei
Materiali, Università di Milano—Bicocca, via R. Cozzi 55, 20125 Milano, Italy
| | - Giovanni Di Liberto
- Dipartimento di Scienza dei
Materiali, Università di Milano—Bicocca, via R. Cozzi 55, 20125 Milano, Italy
| | - Sergio Tosoni
- Dipartimento di Scienza dei
Materiali, Università di Milano—Bicocca, via R. Cozzi 55, 20125 Milano, Italy
| | - Gianfranco Pacchioni
- Dipartimento di Scienza dei
Materiali, Università di Milano—Bicocca, via R. Cozzi 55, 20125 Milano, Italy
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Haug L, Roth JP, Thaler M, Steiner D, Menzel A, Tosoni S, Pacchioni G, Bertel E. Precursor chemistry of h-BN: adsorption, desorption, and decomposition of borazine on Pt(110). Phys Chem Chem Phys 2020; 22:11704-11712. [PMID: 32407428 DOI: 10.1039/d0cp00112k] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Adsorption, desorption and fragmentation of borazine on Pt(110) are studied by temperature-programmed desorption, ultraviolet photoemission spectroscopy, workfunction measurements and density functional theory. Borazine adsorbs in part dissociatively, forming an upright (B3N3H5˙)ads adsorption complex. Radicals with a N-Pt bond are weakly bound and desorb recombinatively following second-order kinetics. Radicals with a B-Pt bond are similar in binding strength to the molecularly adsorbed species, which binds through dispersive forces to the (111) facets of the (1 × 2) reconstructed Pt(110). Both do not desorb but are dehydrogenated beyond T = 150 K. As T approaches 600 K the B-N ring progressively breaks down into its atomic constituents. The borazine ice multilayer is capable of trapping significant amounts of hydrogen. Previous studies of borazine adsorption on other transition metal surfaces yield a very similar pattern. Reported multiple molecular desorption peaks are artefacts. Implications for the nucleation and growth of h-BN monolayers at high temperatures are discussed.
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Affiliation(s)
- Leander Haug
- Institute of Physical Chemistry, University of Innsbruck, Innrain 52c, 6020 Innsbruck, Austria.
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Di Liberto G, Tosoni S, Illas F, Pacchioni G. Nature of SrTiO3/TiO2 (anatase) heterostructure from hybrid density functional theory calculations. J Chem Phys 2020; 152:184704. [DOI: 10.1063/5.0007138] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Affiliation(s)
- Giovanni Di Liberto
- Dipartimento di Scienza dei Materiali, Università di Milano Bicocca, via Roberto Cozzi 55, 20125 Milano, Italy
| | - Sergio Tosoni
- Dipartimento di Scienza dei Materiali, Università di Milano Bicocca, via Roberto Cozzi 55, 20125 Milano, Italy
| | - Francesc Illas
- Departament de Ciència de Materials i Química Física and Institut de Química Teòrica i Computacional (IQTCUB), Universitat de Barcelona, c/Martí i Franquès 1-11, 08028 Barcelona, Spain
| | - Gianfranco Pacchioni
- Dipartimento di Scienza dei Materiali, Università di Milano Bicocca, via Roberto Cozzi 55, 20125 Milano, Italy
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