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Bühlmeyer H, Talwar T, Eschenbacher R, Barreto J, Hauner J, Knörr L, Steinrück HP, Maier F, Libuda J. Surface Chemistry of a [C 2C 1Im][OTf] (Sub)Wetting Layer on Pt(111): A Combined XPS, IRAS, and STM Study. ACS Appl Mater Interfaces 2024. [PMID: 38652177 DOI: 10.1021/acsami.4c02239] [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: 04/25/2024]
Abstract
The concept of a solid catalyst with an ionic liquid layer (SCILL) is a promising approach to improve the selectivity of noble metal catalysts in heterogeneous reactions. In order to understand the origins of this selectivity control, we investigated the growth and thermal stability of ultrathin 1-ethyl-3-methylimidazolium trifluormethanesulfonate [C2C1Im][OTf] films on Pt(111) by infrared reflection absorption spectroscopy (IRAS) and X-ray photoelectron spectroscopy (XPS) in time-resolved and temperature-programmed experiments. We combined these spectroscopy experiments with scanning tunneling microscopy (STM) to obtain detailed insights into the orientation and adsorption geometry of the ions in the first IL layer. Furthermore, we propose a mechanism for the thermal evolution of [C2C1Im][OTf] on Pt(111). We observe an intact IL layer on the surface at temperatures below 200 K. Adsorbed [C2C1Im][OTf] forms islands, which are evenly distributed over the surface. The [OTf]- anion adsorbs via the SO3 group, with the molecular axis perpendicular to the surface. Anions and cations are arranged next to each other, alternating on the Pt(111) surface. Upon heating to 250 K, we observe changes in geometry and structural distribution. Whereas at low temperature, the ions are arranged alternately for electrostatic reasons, this driving force is no longer decisive at 250 K. Here, a phase separation of two different species is discernible in STM. We propose that this effect is due to a surface reaction, which changes the charge of the adsorbates. We assume that the IL starts to decompose at around 250 K, and thus, pristine IL and decomposition products coexist on the surface. Also, IRAS and XPS show indication of IL decomposition. Further heating leads to increased IL decomposition. The reaction products associated with the anions are volatile and leave the surface. In contrast, the cation fragments remain on the surface up to temperatures above 420 K.
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Affiliation(s)
- Hanna Bühlmeyer
- Interface Research and Catalysis, ECRC, Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstraße 3, 91058 Erlangen, Germany
| | - Timo Talwar
- Chair of Physical Chemistry II, Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstraße 3, 91058 Erlangen, Germany
| | - Roman Eschenbacher
- Interface Research and Catalysis, ECRC, Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstraße 3, 91058 Erlangen, Germany
| | - Jade Barreto
- Chair of Physical Chemistry II, Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstraße 3, 91058 Erlangen, Germany
| | - Jonas Hauner
- Interface Research and Catalysis, ECRC, Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstraße 3, 91058 Erlangen, Germany
| | - Lukas Knörr
- Interface Research and Catalysis, ECRC, Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstraße 3, 91058 Erlangen, Germany
| | - Hans-Peter Steinrück
- Chair of Physical Chemistry II, Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstraße 3, 91058 Erlangen, Germany
| | - Florian Maier
- Chair of Physical Chemistry II, Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstraße 3, 91058 Erlangen, Germany
| | - Jörg Libuda
- Interface Research and Catalysis, ECRC, Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstraße 3, 91058 Erlangen, Germany
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Xu Y, Zhang L, Chen W, Cui H, Cai J, Chen Y, Feliu JM, Herrero E. Boosting Oxygen Reduction at Pt(111)|Proton Exchange Ionomer Interfaces through Tuning the Microenvironment Water Activity. ACS Appl Mater Interfaces 2024; 16:4540-4549. [PMID: 38227931 DOI: 10.1021/acsami.3c14208] [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: 01/18/2024]
Abstract
A proton exchange ionomer is one of the most important components in membrane electrode assemblies (MEAs) of polymer electrolyte membrane fuel cells (PEMFCs). It acts as both a proton conductor and a binder for nanocatalysts and carbon supports. The structure and the wetting conditions of the MEAs have a great impact on the microenvironment at the three-phase interphases in the MEAs, which can significantly influence the electrode kinetics such as the oxygen reduction reaction (ORR) at the cathode. Herein, by using the Pt(111)|X ionomer interface as a model system (X = Nafion, Aciplex, D72), we find that higher drying temperature lowers the onset potential for sulfonate adsorption and reduces apparent ORR current, while the current wave for OHad formation drops and shifts positively. Surprisingly, the intrinsic ORR activity is higher after properly correcting the blocking effect of Pt active sites by sulfonate adsorption and the poly(tetrafluoroethylene) (PTFE) skeleton. These results are well explained by the reduced water activity at the interfaces induced by the ionomer/PTFE, according to the mixed potential effect. Implications for how to prepare MEAs with improved ORR activity are provided.
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Affiliation(s)
- Yujun Xu
- Hefei National Research Center for Physical Sciences at Microscale, Department of Chemical Physics, University of Science and Technology of China, Hefei 230026, China
| | - Lulu Zhang
- Hefei National Research Center for Physical Sciences at Microscale, Department of Chemical Physics, University of Science and Technology of China, Hefei 230026, China
| | - Wei Chen
- Hefei National Research Center for Physical Sciences at Microscale, Department of Chemical Physics, University of Science and Technology of China, Hefei 230026, China
| | - Haowen Cui
- Hefei National Research Center for Physical Sciences at Microscale, Department of Chemical Physics, University of Science and Technology of China, Hefei 230026, China
| | - Jun Cai
- Hefei National Research Center for Physical Sciences at Microscale, Department of Chemical Physics, University of Science and Technology of China, Hefei 230026, China
| | - Yanxia Chen
- Hefei National Research Center for Physical Sciences at Microscale, Department of Chemical Physics, University of Science and Technology of China, Hefei 230026, China
| | - Juan M Feliu
- Instituto de Electroquímica, Universidad de Alicante, Apdo. 99, Alicante E-03080, Spain
| | - Enrique Herrero
- Instituto de Electroquímica, Universidad de Alicante, Apdo. 99, Alicante E-03080, Spain
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Ojha K, Doblhoff-Dier K, Koper MTM. Double-layer structure of the Pt(111)-aqueous electrolyte interface. Proc Natl Acad Sci U S A 2022; 119:e2116016119. [PMID: 35042778 DOI: 10.1073/pnas.2116016119] [Citation(s) in RCA: 24] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/27/2021] [Indexed: 11/18/2022] Open
Abstract
We present detailed measurements of the double-layer capacitance of the Pt(111)-electrolyte interface close to the potential of zero charge (PZC) in the presence of several different electrolytes consisting of anions and cations that are considered to be nonspecifically adsorbed. For low electrolyte concentrations, we show strong deviations from traditional Gouy-Chapman-Stern (GCS) behavior that appear to be independent of the nature of the electrolyte ions. Focusing on the capacitance further away from PZC and the trends for increasing ion concentration, we observe ion-specific capacitance effects that appear to be related to the size or hydration strength of the ions. We formulate a model for the structure of the electric double layer of the Pt(111)-electrolyte interface that goes significantly beyond the GCS theory. By combining two existing models, namely, one capturing the water reorganization on Pt close to the PZC and one accounting for an attractive ion-surface interaction not included in the GCS model, we can reproduce and interpret the main features the experimental capacitance of the Pt(111)-electrolyte interface. The model suggests a picture of the double layer with an increased ion concentration close to the interface as a consequence of a weak attractive ion-surface interaction, and a changing polarizability of the Pt(111)-water interface due to the potential-dependent water adsorption and orientation.
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Haid RW, Kluge RM, Liang Y, Bandarenka AS. In Situ Quantification of the Local Electrocatalytic Activity via Electrochemical Scanning Tunneling Microscopy. Small Methods 2021; 5:e2000710. [PMID: 34927879 DOI: 10.1002/smtd.202000710] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Revised: 09/10/2020] [Indexed: 06/14/2023]
Abstract
Identification of catalytically active sites at solid/liquid interfaces under reaction conditions is an essential task to improve the catalyst design for sustainable energy devices. Electrochemical scanning tunneling microscopy (EC-STM) combines the control of the surface reactions with imaging on a nanoscale. When performing EC-STM under reaction conditions, the recorded analytical signal shows higher fluctuations (noise) at active sites compared to non-active sites (noise-EC-STM or n-EC-STM). In the past, this approach has been proven as a valid tool to identify the location of active sites. In this work, the authors show that this method can be extended to obtain quantitative information of the local activity. For the platinum(111) surface under oxygen reduction reaction conditions, a linear relationship between the STM noise level and a measure of reactivity, the turn-over frequency is found. Since it is known that the most active sites for this system are located at concave sites, the method has been applied to quantify the activity at steps. The obtained activity enhancement factors appeared to be in good agreement with the literature. Thus, n-EC-STM is a powerful method not only to in situ identify the location of active sites but also to determine and compare local reactivity.
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Affiliation(s)
- Richard W Haid
- Department of Physics (ECS), Technical University of Munich, James-Franck-Straße 1, Garching, 85748, Germany
| | - Regina M Kluge
- Department of Physics (ECS), Technical University of Munich, James-Franck-Straße 1, Garching, 85748, Germany
| | - Yunchang Liang
- Department of Physics (ECS), Technical University of Munich, James-Franck-Straße 1, Garching, 85748, Germany
| | - Aliaksandr S Bandarenka
- Department of Physics (ECS), Technical University of Munich, James-Franck-Straße 1, Garching, 85748, Germany
- Catalysis Research Center TUM, Ernst-Otto-Fischer-Straße 1, Garching, 85748, Germany
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Abstract
CO adlayers on Pt(111) electrode surfaces are an important electrochemical system and of great relevance to electrocatalysis. The potential-dependent structure and dynamics of these adlayers are complex and still controversial, especially in the CO pre-oxidation regime. We here employ in situ high-speed scanning tunneling microscopy for studying the surface phase behavior in CO-saturated 0.1 m H2 SO4 on the millisecond time scale. At potentials near the onset of CO pre-oxidation local fluctuations in the (2×2)-CO adlayer are observed, which increase towards more positive potentials. Above 0.20 V (vs. Ag/AgCl), this leads to an adlayer where COad apparently reside on every top site, but still exhibit a (2×2) superstructure modulation. We interpret this observation as a dynamic effect, caused by a small number of highly mobile point defects in the (2×2)-CO adlayer. As shown by density functional theory calculations, the CO lattice near such defects relaxes into a local (1×1) arrangement, which can rapidly propagate across the surface. This scenario, where a static (2×2) COad sublattice coexists with a highly dynamic sublattice of partially occupied top sites, explains the pronounced COad surface mobility during electrooxidation.
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Affiliation(s)
- Jie Wei
- Institute of Experimental and Applied PhysicsKiel University24098KielGermany
- Hefei National Laboratory for Physical Sciences at MicroscaleUniversity of Science and Technology of ChinaHefei230026China
| | | | - Yan‐Xia Chen
- Hefei National Laboratory for Physical Sciences at MicroscaleUniversity of Science and Technology of ChinaHefei230026China
| | - Sung Sakong
- Institute of Theoretical ChemistryUlm UniversityAlbert-Einstein-Allee 1189081UlmGermany
| | - Axel Gross
- Institute of Theoretical ChemistryUlm UniversityAlbert-Einstein-Allee 1189081UlmGermany
| | - Olaf M. Magnussen
- Institute of Experimental and Applied PhysicsKiel University24098KielGermany
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Ojha K, Arulmozhi N, Aranzales D, Koper MTM. Double Layer at the Pt(111)-Aqueous Electrolyte Interface: Potential of Zero Charge and Anomalous Gouy-Chapman Screening. Angew Chem Int Ed Engl 2019; 59:711-715. [PMID: 31682314 PMCID: PMC6973170 DOI: 10.1002/anie.201911929] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [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: 09/18/2019] [Revised: 10/30/2019] [Indexed: 12/02/2022]
Abstract
We report, for the first time, the observation of a Gouy–Chapman capacitance minimum at the potential of zero charge of the Pt(111)‐aqueous perchlorate electrolyte interface. The potential of zero charge of 0.3 V vs. NHE agrees very well with earlier values obtained by different methods. The observation of the potential of zero charge of this interface requires a specific pH (pH 4) and anomalously low electrolyte concentrations (<10−3
m). By comparison to gold and mercury double‐layer data, we conclude that the diffuse double layer structure at the Pt(111)‐electrolyte interface deviates significantly from the Gouy–Chapman theory in the sense that the electrostatic screening is much better than predicted by purely electrostatic mean‐field Poisson–Boltzmann theory.
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Affiliation(s)
- Kasinath Ojha
- Leiden Institute of Chemistry, Leiden University, 2300, RA, Leiden, The Netherlands
| | - Nakkiran Arulmozhi
- Leiden Institute of Chemistry, Leiden University, 2300, RA, Leiden, The Netherlands
| | - Diana Aranzales
- Leiden Institute of Chemistry, Leiden University, 2300, RA, Leiden, The Netherlands
| | - Marc T M Koper
- Leiden Institute of Chemistry, Leiden University, 2300, RA, Leiden, The Netherlands
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Wang S, Feng Y, Yu M, Wan Q, Lin S. Confined Catalysis in the g-C 3N 4/ Pt(111) Interface: Feasible Molecule Intercalation, Tunable Molecule-Metal Interaction, and Enhanced Reaction Activity of CO Oxidation. ACS Appl Mater Interfaces 2017; 9:33267-33273. [PMID: 28876886 DOI: 10.1021/acsami.7b08665] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The deposition of a two-dimensional (2D) atomic nanosheet on a metal surface has been considered as a new route for tuning the molecule-metal interaction and surface reactivity in terms of the confinement effect. In this work, we use first-principles calculations to systematically explore a novel nanospace constructed by placing a 2D graphitic carbon nitride (g-C3N4) nanosheet over a Pt(111) surface. The confined catalytic activity in this nanospace is investigated using CO oxidation as a model reaction. With the inherent triangular pores in the g-C3N4 overlayer being taken advantage of, molecules such as CO and O2 can diffuse to adsorb on the Pt(111) surface underneath the g-C3N4 overlayer. Moreover, the mechanism of intercalation is also elucidated, and the results reveal that the energy barrier depends mainly on the properties of the molecule and the channel. Importantly, the molecule-catalyst interaction can be tuned by the g-C3N4 overlayer, considerably reducing the adsorption energy of CO on Pt(111) and leading to enhanced reactivity in CO oxidation. This work will provide important insight for constructing a promising nanoreactor in which the following is observed: The molecule intercalation is facile; the molecule-metal interaction is efficiently tuned; the metal-catalyzed reaction is promoted.
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Affiliation(s)
- Shujiao Wang
- State Key Laboratory of Photocatalysis on Energy and Environment, College of Chemistry, Fuzhou University , Fuzhou 350002, China
| | - Yingxin Feng
- State Key Laboratory of Photocatalysis on Energy and Environment, College of Chemistry, Fuzhou University , Fuzhou 350002, China
| | - Ming'an Yu
- State Key Laboratory of Photocatalysis on Energy and Environment, College of Chemistry, Fuzhou University , Fuzhou 350002, China
| | - Qiang Wan
- State Key Laboratory of Photocatalysis on Energy and Environment, College of Chemistry, Fuzhou University , Fuzhou 350002, China
| | - Sen Lin
- State Key Laboratory of Photocatalysis on Energy and Environment, College of Chemistry, Fuzhou University , Fuzhou 350002, China
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8
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Chen J, Luo S, Liu Y, Chen S. Theoretical Analysis of Electrochemical Formation and Phase Transition of Oxygenated Adsorbates on Pt(111). ACS Appl Mater Interfaces 2016; 8:20448-20458. [PMID: 27377100 DOI: 10.1021/acsami.6b04545] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The electrochemical oxygenation processes of Pt(111) surface are investigated by combining density functional theory (DFT) calculations and Monto Carlo (MC) simulations. DFT calculations are performed to construct force-field parameters for computing the energy of (√3 × √3)R30°-structured OH*-H2O* hydrogen-bonding networks (differently dissociated water bilayer) on the Pt(111) surface, with which MC simulations are conducted to probe the reversible H2O* ↔ OH* conversion in OH*-H2O* networks. The simulated isotherm (relation between electrode potential and OH* coverage) agrees well with that predicted by the experimental cyclic voltammetry (CV) in the potential region of 0.55-0.85 V (vs RHE). It is suggested that the butterfly shape of CV in this region is due to different variation trends of Pt-H2O* distance in low and high OH* coverages. DFT calculation results indicate that the oxidative voltammetry in the potential region from 0.85 V to ca. 1.07 V is associated with the dissociation of OH* to O*, which yields surface structures consisting of OH*-H2O* networks and (√3 × √3)-structured O* clusters. The high stability of the half-dissociated water bilayer (OH*-H2O* hydrogen-bonding network with equal OH* and H2O* coverages) formed in the butterfly region makes OH* dissociation initially very difficult in energetics, but become facile once starts due to the destabilization of OH* by the formed O* nearby. This explains the experimentally observed nucleation and growth behavior of O* phase formation and the high asymmetry of oxidation-reduction voltammetry in this potential region.
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Affiliation(s)
- Junxiang Chen
- Hubei Key Laboratory of Electrochemical Power Sources, Key Laboratory of Analytical Chemistry for Biology and Medicine (Ministry of Education), Department of Chemistry, Wuhan University , Wuhan 430072, China
| | - Siwei Luo
- Hubei Key Laboratory of Electrochemical Power Sources, Key Laboratory of Analytical Chemistry for Biology and Medicine (Ministry of Education), Department of Chemistry, Wuhan University , Wuhan 430072, China
| | - Yuwen Liu
- Hubei Key Laboratory of Electrochemical Power Sources, Key Laboratory of Analytical Chemistry for Biology and Medicine (Ministry of Education), Department of Chemistry, Wuhan University , Wuhan 430072, China
| | - Shengli Chen
- Hubei Key Laboratory of Electrochemical Power Sources, Key Laboratory of Analytical Chemistry for Biology and Medicine (Ministry of Education), Department of Chemistry, Wuhan University , Wuhan 430072, China
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Herron JA, Morikawa Y, Mavrikakis M. Ab initio molecular dynamics of solvation effects on reactivity at electrified interfaces. Proc Natl Acad Sci U S A 2016; 113:E4937-45. [PMID: 27503889 DOI: 10.1073/pnas.1604590113] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Using ab initio molecular dynamics as implemented in periodic, self-consistent (generalized gradient approximation Perdew-Burke-Ernzerhof) density functional theory, we investigated the mechanism of methanol electrooxidation on Pt(111). We investigated the role of water solvation and electrode potential on the energetics of the first proton transfer step, methanol electrooxidation to methoxy (CH3O) or hydroxymethyl (CH2OH). The results show that solvation weakens the adsorption of methoxy to uncharged Pt(111), whereas the binding energies of methanol and hydroxymethyl are not significantly affected. The free energies of activation for breaking the C-H and O-H bonds in methanol were calculated through a Blue Moon Ensemble using constrained ab initio molecular dynamics. Calculated barriers for these elementary steps on unsolvated, uncharged Pt(111) are similar to results for climbing-image nudged elastic band calculations from the literature. Water solvation reduces the barriers for both C-H and O-H bond activation steps with respect to their vapor-phase values, although the effect is more pronounced for C-H bond activation, due to less disruption of the hydrogen bond network. The calculated activation energy barriers show that breaking the C-H bond of methanol is more facile than the O-H bond on solvated negatively biased or uncharged Pt(111). However, with positive bias, O-H bond activation is enhanced, becoming slightly more facile than C-H bond activation.
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Otero-Irurueta G, Martínez JI, Bueno R, Palomares FJ, Salavagione HJ, Singh MK, Méndez J, Ellis GJ, López MF, Martín-Gago JA. Adsorption and Coupling of 4-aminophenol on Pt(111) surfaces. Surf Sci 2015; 646:5-12. [PMID: 27279673 PMCID: PMC4894458 DOI: 10.1016/j.susc.2015.08.039] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
We have deposited 4-aminophenol on Pt(111) surfaces in ultra-high vacuum and studied the strength of its adsorption through a combination of STM, LEED, XPS and ab initio calculations. Although an ordered (2√3×2√3)R30° phase appears, we have observed that molecule-substrate interaction dominates the adsorption geometry and properties of the system. At RT the high catalytic activity of Pt induces aminophenol to lose the H atom from the hydroxyl group, and a proportion of the molecules lose the complete hydroxyl group. After annealing above 420K, all deposited aminophenol molecules have lost the OH moiety and some hydrogen atoms from the amino groups. At this temperature, short single-molecule oligomer chains can be observed. These chains are the product of a new reaction that proceeds via the coupling of radical species that is favoured by surface diffusion.
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Affiliation(s)
- G. Otero-Irurueta
- ESISNA Group, Dept. Surfaces, Coatings and Molecular Astrophysics, Institute of Material Science of Madrid (ICMM-CSIC), Sor Juana Inés de la Cruz 3, 28049 Madrid, Spain
- Center for Mechanical Technology and Automation (TEMA), Department of Mechanical Engineering, University of Aveiro, 3810-193 Aveiro, Portugal
| | - J. I. Martínez
- ESISNA Group, Dept. Surfaces, Coatings and Molecular Astrophysics, Institute of Material Science of Madrid (ICMM-CSIC), Sor Juana Inés de la Cruz 3, 28049 Madrid, Spain
| | - R.A. Bueno
- ESISNA Group, Dept. Surfaces, Coatings and Molecular Astrophysics, Institute of Material Science of Madrid (ICMM-CSIC), Sor Juana Inés de la Cruz 3, 28049 Madrid, Spain
| | - F. J. Palomares
- ESISNA Group, Dept. Surfaces, Coatings and Molecular Astrophysics, Institute of Material Science of Madrid (ICMM-CSIC), Sor Juana Inés de la Cruz 3, 28049 Madrid, Spain
| | - H. J. Salavagione
- Polymer Physics Group, Dept. Polymer Physics, Elastomers and Energy Applications, Institute of Polymer Science and Technology (ICTP-CSIC), Juan de la Cierva 3, 28006 Madrid, Spain
| | - M. K. Singh
- Center for Mechanical Technology and Automation (TEMA), Department of Mechanical Engineering, University of Aveiro, 3810-193 Aveiro, Portugal
| | - J. Méndez
- ESISNA Group, Dept. Surfaces, Coatings and Molecular Astrophysics, Institute of Material Science of Madrid (ICMM-CSIC), Sor Juana Inés de la Cruz 3, 28049 Madrid, Spain
| | - G. J. Ellis
- Polymer Physics Group, Dept. Polymer Physics, Elastomers and Energy Applications, Institute of Polymer Science and Technology (ICTP-CSIC), Juan de la Cierva 3, 28006 Madrid, Spain
| | - M. F. López
- ESISNA Group, Dept. Surfaces, Coatings and Molecular Astrophysics, Institute of Material Science of Madrid (ICMM-CSIC), Sor Juana Inés de la Cruz 3, 28049 Madrid, Spain
| | - J. A. Martín-Gago
- ESISNA Group, Dept. Surfaces, Coatings and Molecular Astrophysics, Institute of Material Science of Madrid (ICMM-CSIC), Sor Juana Inés de la Cruz 3, 28049 Madrid, Spain
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11
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Zhang Y, Weng X, Li H, Li H, Wei M, Xiao J, Liu Z, Chen M, Fu Q, Bao X. Hexagonal boron nitride cover on Pt(111): a new route to tune molecule-metal interaction and metal-catalyzed reactions. Nano Lett 2015; 15:3616-23. [PMID: 25897635 DOI: 10.1021/acs.nanolett.5b01205] [Citation(s) in RCA: 79] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
In heterogeneous catalysis molecule-metal interaction is often modulated through structural modifications at the surface or under the surface of the metal catalyst. Here, we suggest an alternative way toward this modulation by placing a two-dimensional (2D) cover on the metal surface. As an illustration, CO adsorption on Pt(111) surface has been studied under 2D hexagonal boron nitride (h-BN) overlayer. Dynamic imaging data from surface electron microscopy and in situ surface spectroscopic results under near ambient pressure conditions confirm that CO molecules readily intercalate monolayer h-BN sheets on Pt(111) in CO atmosphere but desorb from the h-BN/Pt(111) interface even around room temperature in ultrahigh vacuum. The interaction of CO with Pt has been strongly weakened due to the confinement effect of the h-BN cover, and consequently, CO oxidation at the h-BN/Pt(111) interface was enhanced thanks to the alleviated CO poisoning effect.
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Affiliation(s)
- Yanhong Zhang
- †State Key Laboratory of Catalysis, iChEM, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, P.R. China
| | - Xuefei Weng
- ‡State Key Laboratory of Physical Chemistry of Solid Surfaces, Department of Chemistry, Xiamen University, Xiamen 361005, P.R. China
| | - Huan Li
- ‡State Key Laboratory of Physical Chemistry of Solid Surfaces, Department of Chemistry, Xiamen University, Xiamen 361005, P.R. China
| | - Haobo Li
- †State Key Laboratory of Catalysis, iChEM, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, P.R. China
| | - Mingming Wei
- †State Key Laboratory of Catalysis, iChEM, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, P.R. China
| | - Jianping Xiao
- †State Key Laboratory of Catalysis, iChEM, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, P.R. China
| | - Zhi Liu
- §Advanced Light Source, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94720, United States
| | - Mingshu Chen
- ‡State Key Laboratory of Physical Chemistry of Solid Surfaces, Department of Chemistry, Xiamen University, Xiamen 361005, P.R. China
| | - Qiang Fu
- †State Key Laboratory of Catalysis, iChEM, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, P.R. China
| | - Xinhe Bao
- †State Key Laboratory of Catalysis, iChEM, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, P.R. China
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Rana M, Chhetri M, Loukya B, Patil PK, Datta R, Gautam UK. High-yield synthesis of sub-10 nm Pt nanotetrahedra with bare ⟨111⟩ facets for efficient electrocatalytic applications. ACS Appl Mater Interfaces 2015; 7:4998-5005. [PMID: 25660263 DOI: 10.1021/acsami.5b00211] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Unlike other shapes, the design of tetrahedral Pt nanocrystals (Pt-NTd), which have the largest number of Pt(111) surface atoms and highest catalytic activities toward the electron transfer reactions, has widely been considered a synthetic challenge due to their thermodynamic instability. Here, we show that, by inducing their nucleation on functionalized carbon, Pt NTds can be obtained with tunable sizes and high yields. The carbon support anchors the nanocrystals early and prevents their oriented attachment leading to nanowire formation. Therein, an in situ generated amine is crucial for stabilization of Pt-NTds, which can later be removed to expose the Pt(111) facets for higher catalytic efficiency. The bare nanocrystals exhibit much improved stability and electrocatalytic activity characteristic of Pt(111) toward oxygen reduction reaction (ORR) and methanol and formic acid oxidation reactions. For example, ∼90% of their activity was retained after 5000 potential cycles, while the ORR onset potential was recorded to be very high, 1.01 V vs reversible hydrogen electrode (RHE).
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Affiliation(s)
- Moumita Rana
- New Chemistry Unit, ∥International Centre for Materials Science, Jawaharlal Nehru Centre for Advanced Scientific Research , Bangalore 560064, India
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Gómez-Marín AM, Rizo R, Feliu JM. Some reflections on the understanding of the oxygen reduction reaction at Pt(111). Beilstein J Nanotechnol 2013; 4:956-67. [PMID: 24455454 PMCID: PMC3896285 DOI: 10.3762/bjnano.4.108] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2013] [Accepted: 12/13/2013] [Indexed: 05/04/2023]
Abstract
The oxygen reduction reaction (ORR) is a pivotal process in electrochemistry. Unfortunately, after decades of intensive research, a fundamental knowledge about its reaction mechanism is still lacking. In this paper, a global and critical view on the most important experimental and theoretical results regarding the ORR on Pt(111) and its vicinal surfaces, in both acidic and alkaline media, is taken. Phenomena such as the ORR surface structure sensitivity and the lack of a reduction current at high potentials are discussed in the light of the surface oxidation and disordering processes and the possible relevance of the hydrogen peroxide reduction and oxidation reactions in the ORR mechanism. The necessity to build precise and realistic reaction models, which are deducted from reliable experimental results that need to be carefully taken under strict working conditions is shown. Therefore, progress in the understanding of this important reaction on a molecular level, and the choice of the right approach for the design of the electrocatalysts for fuel-cell cathodes is only possible through a cooperative approach between theory and experiments.
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Affiliation(s)
- Ana M Gómez-Marín
- Instituto de Electroquímica, Universidad de Alicante, Apt. 99, Alicante, E-03080, Spain
| | - Ruben Rizo
- Instituto de Electroquímica, Universidad de Alicante, Apt. 99, Alicante, E-03080, Spain
| | - Juan M Feliu
- Instituto de Electroquímica, Universidad de Alicante, Apt. 99, Alicante, E-03080, Spain
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