1
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Sauer C, de Reijer GJL, Wilfinger B, Hellman A, Carlsson PA. Continuous isomerisation of 2,5-dimethylfuran to 2,4-dimethylfuran over Ga-silicate. Chemistry 2024; 30:e202303810. [PMID: 38327129 DOI: 10.1002/chem.202303810] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2023] [Revised: 01/25/2024] [Accepted: 02/08/2024] [Indexed: 02/09/2024]
Abstract
2,4-dimethylfuran has a rare disubstitution pattern in the five-membered heterocyclic furan ring that is highly interesting chemically but challenging to access synthetically. We present a heterogeneously catalysed route to synthesise 2,4-dimethylfuran from commonly available 2,5-dimethylfuran using a zeolite packed-bed flow reactor. As supported by DFT calculations, the reaction occurs inside the zeolite channels, where the acid sites catalyse proton transfer followed by migration of a methyl group. The zeotype Ga-silicate (MFI type) appears superior to an aluminium-containing ZSM-5 by demonstrating higher selectivities and slower catalyst deactivation. This work provides new opportunities for the continuous valorisation of bio-feedstock molecules in the perspective of the emerging biorefinery era.
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Affiliation(s)
- Christopher Sauer
- Department of Chemistry and Chemical Engineering, Chalmers University of Technology, SE-412 96, Gothenburg, Sweden
| | - Guido J L de Reijer
- Department of Chemistry and Chemical Engineering, Chalmers University of Technology, SE-412 96, Gothenburg, Sweden
| | - Barbara Wilfinger
- Department of Physics, Chalmers University of Technology, SE-412 96, Gothenburg, Sweden
| | - Anders Hellman
- Department of Physics, Chalmers University of Technology, SE-412 96, Gothenburg, Sweden
| | - Per-Anders Carlsson
- Department of Chemistry and Chemical Engineering, Chalmers University of Technology, SE-412 96, Gothenburg, Sweden
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2
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Hus M, Grilc M, Teržan J, Gyergyek S, Likozar B, Hellman A. Going beyond Silver in Ethylene Epoxidation with First-Principles Catalyst Screening. Angew Chem Int Ed Engl 2023:e202305804. [PMID: 37226934 DOI: 10.1002/anie.202305804] [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: 04/25/2023] [Revised: 05/22/2023] [Accepted: 05/25/2023] [Indexed: 05/26/2023]
Abstract
Ethylene epoxidation is industrially and commercially one of the most important selective oxidations. Silver catalysts have been state-of-the-art for decades, their efficiency steadily improving with empirical discoveries of dopants and co-catalysts. Herein, we perform a computational screening of the metals in the periodic table, identify prospective superior catalysts and experimentally demonstrate that Ag/CuPb, Ag/CuCd and Ag/CuTl outperform the pure-Ag catalysts, while they still confer an easily scalable synthesis protocol. Furthermore, we show that to harness the potential of computationally-led discovery of catalysts fully, it is essential to include the relevant \textit{in-situ} conditions e.g., surface oxidation, parasitic side reactions and ethylene epoxide decomposition, as neglecting such effects leads to erroneous predictions. We combine \textit{ab initio} calculations, scaling relations, and rigorous reactor microkinetic modelling, which goes beyond conventional simplified steady-state or rate-determining modelling on immutable catalyst surfaces. The modelling insights have enabled us to both synthesise novel catalysts and theoretically understand experimental findings, thus, bridging the gap between first-principles simulations and industrial applications. We show that the computational catalyst design can be easily extended to include larger reaction networks and other effects, such as surface oxidations. The feasibility was confirmed by experimental agreement.
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Affiliation(s)
- Matej Hus
- Chalmers University of Technology: Chalmers tekniska hogskola AB, Department of Physics, SWEDEN
| | - Miha Grilc
- National Institute of Chemistry Slovenia: Kemijski institut, Department of Catalysis and Chemical Reaction Engineering, SLOVENIA
| | - Janvit Teržan
- National Institute of Chemistry Slovenia: Kemijski institut, Department of Catalysis and Chemical Reaction Engineering, SLOVENIA
| | - Sašo Gyergyek
- Institut Jožef Stefan: Institut Jozef Stefan, Department of Material Synthesis, SLOVENIA
| | - Blaž Likozar
- National Institute of Chemistry Slovenia: Kemijski institut, Department of Catalysis and Chemical Reaction Engineering, SLOVENIA
| | - Anders Hellman
- Chalmers University of Technology: Chalmers tekniska hogskola AB, Department of Physics, SWEDEN
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3
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Feng Y, Schaefer A, Hellman A, Di M, Härelind H, Bauer M, Carlsson PA. Synthesis and Characterization of Catalytically Active Au Core─Pd Shell Nanoparticles Supported on Alumina. Langmuir 2022; 38:12859-12870. [PMID: 36221959 PMCID: PMC9609311 DOI: 10.1021/acs.langmuir.2c01834] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Revised: 09/30/2022] [Indexed: 06/16/2023]
Abstract
A two-step seeded-growth method was refined to synthesize Au@Pd core@shell nanoparticles with thin Pd shells, which were then deposited onto alumina to obtain a supported Au@Pd/Al2O3 catalyst active for prototypical CO oxidation. By the strict control of temperature and Pd/Au molar ratio and the use of l-ascorbic acid for making both Au cores and Pd shells, a 1.5 nm Pd layer is formed around the Au core, as evidenced by transmission electron microscopy and energy-dispersive spectroscopy. The core@shell structure and the Pd shell remain intact upon deposition onto alumina and after being used for CO oxidation, as revealed by additional X-ray diffraction and X-ray photoemission spectroscopy before and after the reaction. The Pd shell surface was characterized with in situ infrared (IR) spectroscopy using CO as a chemical probe during CO adsorption-desorption. The IR bands for CO ad-species on the Pd shell suggest that the shell exposes mostly low-index surfaces, likely Pd(111) as the majority facet. Generally, the IR bands are blue-shifted as compared to conventional Pd/alumina catalysts, which may be due to the different support materials for Pd, Au versus Al2O3, and/or less strain of the Pd shell. Frequencies obtained from density functional calculations suggest the latter to be significant. Further, the catalytic CO oxidation ignition-extinction processes were followed by in situ IR, which shows the common CO poisoning and kinetic behavior associated with competitive adsorption of CO and O2 that is typically observed for noble metal catalysts.
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Affiliation(s)
- Yanyue Feng
- Department
of Chemistry and Chemical Engineering, Chalmers
University of Technology, SE-412 96Gothenburg, Sweden
| | - Andreas Schaefer
- Department
of Chemistry and Chemical Engineering, Chalmers
University of Technology, SE-412 96Gothenburg, Sweden
| | - Anders Hellman
- Department
of Physics, Chalmers University of Technology, SE-412 96Gothenburg, Sweden
| | - Mengqiao Di
- Department
of Chemistry and Chemical Engineering, Chalmers
University of Technology, SE-412 96Gothenburg, Sweden
| | - Hanna Härelind
- Department
of Chemistry and Chemical Engineering, Chalmers
University of Technology, SE-412 96Gothenburg, Sweden
| | - Matthias Bauer
- Department
of Chemistry, Paderborn University, 33098Paderborn, Germany
| | - Per-Anders Carlsson
- Department
of Chemistry and Chemical Engineering, Chalmers
University of Technology, SE-412 96Gothenburg, Sweden
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4
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Levin S, Lerch S, Boje A, Fritzsche J, KK S, Ström H, Moth-Poulsen K, Sundén H, Hellman A, Westerlund F, Langhammer C. Nanofluidic Trapping of Faceted Colloidal Nanocrystals for Parallel Single-Particle Catalysis. ACS Nano 2022; 16:15206-15214. [PMID: 36054658 PMCID: PMC9527799 DOI: 10.1021/acsnano.2c06505] [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] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/02/2022] [Accepted: 08/31/2022] [Indexed: 06/15/2023]
Abstract
Catalyst activity can depend distinctly on nanoparticle size and shape. Therefore, understanding the structure sensitivity of catalytic reactions is of fundamental and technical importance. Experiments with single-particle resolution, where ensemble-averaging is eliminated, are required to study it. Here, we implement the selective trapping of individual spherical, cubic, and octahedral colloidal Au nanocrystals in 100 parallel nanofluidic channels to determine their activity for fluorescein reduction by sodium borohydride using fluorescence microscopy. As the main result, we identify distinct structure sensitivity of the rate-limiting borohydride oxidation step originating from different edge site abundance on the three particle types, as confirmed by first-principles calculations. This advertises nanofluidic reactors for the study of structure-function correlations in catalysis and identifies nanoparticle shape as a key factor in borohydride-mediated catalytic reactions.
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Affiliation(s)
- Sune Levin
- Department
of Biology and Biological Engineering, Chalmers
University of Technology; SE-412 96 Gothenburg, Sweden
| | - Sarah Lerch
- Department
of Chemistry and Chemical Engineering, Chalmers
University of Technology; SE-412 96 Gothenburg, Sweden
| | - Astrid Boje
- Department
of Physics, Chalmers University of Technology; SE-412 96 Gothenburg, Sweden
| | - Joachim Fritzsche
- Department
of Physics, Chalmers University of Technology; SE-412 96 Gothenburg, Sweden
| | - Sriram KK
- Department
of Biology and Biological Engineering, Chalmers
University of Technology; SE-412 96 Gothenburg, Sweden
| | - Henrik Ström
- Department
of Mechanics and Maritime Sciences, Chalmers
University of Technology; SE-412 96 Gothenburg, Sweden
- Department
of Energy and Process Engineering, Norwegian
University of Science and Technology; NO-7034 Trondheim, Norway
| | - Kasper Moth-Poulsen
- Department
of Chemistry and Chemical Engineering, Chalmers
University of Technology; SE-412 96 Gothenburg, Sweden
- Institute
of Materials Science of Barcelona, ICMAB-CSIC, Bellaterra, ES-08193 Barcelona, Spain
- Catalan
Institution for Research and Advanced Studies, ICREA; ES-08010 Barcelona, Spain
| | - Henrik Sundén
- Department
of Chemistry and Chemical Engineering, Chalmers
University of Technology; SE-412 96 Gothenburg, Sweden
- Department
of Chemistry & Molecular Biology, University
of Gothenburg; SE-412 96 Gothenburg, Sweden
| | - Anders Hellman
- Department
of Physics, Chalmers University of Technology; SE-412 96 Gothenburg, Sweden
- Competence
Centre for Catalysis, Chalmers University
of Technology; SE-412 96 Gothenburg, Sweden
| | - Fredrik Westerlund
- Department
of Biology and Biological Engineering, Chalmers
University of Technology; SE-412 96 Gothenburg, Sweden
| | - Christoph Langhammer
- Department
of Physics, Chalmers University of Technology; SE-412 96 Gothenburg, Sweden
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Ware J, Boughton CK, Allen JM, Wilinska ME, Tauschmann M, Denvir L, Thankamony A, Campbell FM, Wadwa RP, Buckingham BA, Davis N, DiMeglio LA, Mauras N, Besser REJ, Ghatak A, Weinzimer SA, Hood KK, Fox DS, Kanapka L, Kollman C, Sibayan J, Beck RW, Hovorka R, Hovorka R, Acerini CL, Thankamony A, Allen JM, Boughton CK, Dovc K, Dunger DB, Ware J, Musolino G, Tauschmann M, Wilinska ME, Hayes JF, Hartnell S, Slegtenhorst S, Ruan Y, Haydock M, Mangat J, Denvir L, Kanthagnany SK, Law J, Randell T, Sachdev P, Saxton M, Coupe A, Stafford S, Ball A, Keeton R, Cresswell R, Crate L, Cripps H, Fazackerley H, Looby L, Navarra H, Saddington C, Smith V, Verhoeven V, Bratt S, Khan N, Moyes L, Sandhu K, West C, Wadwa RP, Alonso G, Forlenza G, Slover R, Towers L, Berget C, Coakley A, Escobar E, Jost E, Lange S, Messer L, Thivener K, Campbell FM, Yong J, Metcalfe E, Allen M, Ambler S, Waheed S, Exall J, Tulip J, Buckingham BA, Ekhlaspour L, Maahs D, Norlander L, Jacobson T, Twon M, Weir C, Leverenz B, Keller J, Davis N, Kumaran A, Trevelyan N, Dewar H, Price G, Crouch G, Ensom R, Haskell L, Lueddeke LM, Mauras N, Benson M, Bird K, Englert K, Permuy J, Ponthieux K, Marrero-Hernandez J, DiMeglio LA, Ismail H, Jolivette H, Sanchez J, Woerner S, Kirchner M, Mullen M, Tebbe M, Besser REJ, Basu S, London R, Makaya T, Ryan F, Megson C, Bowen-Morris J, Haest J, Law R, Stamford I, Ghatak A, Deakin M, Phelan K, Thornborough K, Shakeshaft J, Weinzimer SA, Cengiz E, Sherr JL, Van Name M, Weyman K, Carria L, Steffen A, Zgorski M, Sibayan J, Beck RW, Borgman S, Davis J, Rusnak J, Hellman A, Cheng P, Kanapka L, Kollman C, McCarthy C, Chalasani S, Hood KK, Hanes S, Viana J, Lanning M, Fox DS, Arreaza-Rubin G, Eggerman T, Green N, Janicek R, Gabrielson D, Belle SH, Castle J, Green J, Legault L, Willi SM, Wysham C. Cambridge hybrid closed-loop algorithm in children and adolescents with type 1 diabetes: a multicentre 6-month randomised controlled trial. Lancet Digit Health 2022; 4:e245-e255. [PMID: 35272971 DOI: 10.1016/s2589-7500(22)00020-6] [Citation(s) in RCA: 28] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Revised: 12/10/2021] [Accepted: 01/25/2022] [Indexed: 02/07/2023]
Abstract
BACKGROUND Closed-loop insulin delivery systems have the potential to address suboptimal glucose control in children and adolescents with type 1 diabetes. We compared safety and efficacy of the Cambridge hybrid closed-loop algorithm with usual care over 6 months in this population. METHODS In a multicentre, multinational, parallel randomised controlled trial, participants aged 6-18 years using insulin pump therapy were recruited at seven UK and five US paediatric diabetes centres. Key inclusion criteria were diagnosis of type 1 diabetes for at least 12 months, insulin pump therapy for at least 3 months, and screening HbA1c levels between 53 and 86 mmol/mol (7·0-10·0%). Using block randomisation and central randomisation software, we randomly assigned participants to either closed-loop insulin delivery (closed-loop group) or to usual care with insulin pump therapy (control group) for 6 months. Randomisation was stratified at each centre by local baseline HbA1c. The Cambridge closed-loop algorithm running on a smartphone was used with either (1) a modified Medtronic 640G pump, Medtronic Guardian 3 sensor, and Medtronic prototype phone enclosure (FlorenceM configuration), or (2) a Sooil Dana RS pump and Dexcom G6 sensor (CamAPS FX configuration). The primary endpoint was change in HbA1c at 6 months combining data from both configurations. The primary analysis was done in all randomised patients (intention to treat). Trial registration ClinicalTrials.gov, NCT02925299. FINDINGS Of 147 people initially screened, 133 participants (mean age 13·0 years [SD 2·8]; 57% female, 43% male) were randomly assigned to either the closed-loop group (n=65) or the control group (n=68). Mean baseline HbA1c was 8·2% (SD 0·7) in the closed-loop group and 8·3% (0·7) in the control group. At 6 months, HbA1c was lower in the closed-loop group than in the control group (between-group difference -3·5 mmol/mol (95% CI -6·5 to -0·5 [-0·32 percentage points, -0·59 to -0·04]; p=0·023). Closed-loop usage was low with FlorenceM due to failing phone enclosures (median 40% [IQR 26-53]), but consistently high with CamAPS FX (93% [88-96]), impacting efficacy. A total of 155 adverse events occurred after randomisation (67 in the closed-loop group, 88 in the control group), including seven severe hypoglycaemia events (four in the closed-loop group, three in the control group), two diabetic ketoacidosis events (both in the closed-loop group), and two non-treatment-related serious adverse events. There were 23 reportable hyperglycaemia events (11 in the closed-loop group, 12 in the control group), which did not meet criteria for diabetic ketoacidosis. INTERPRETATION The Cambridge hybrid closed-loop algorithm had an acceptable safety profile, and improved glycaemic control in children and adolescents with type 1 diabetes. To ensure optimal efficacy of the closed-loop system, usage needs to be consistently high, as demonstrated with CamAPS FX. FUNDING National Institute of Diabetes and Digestive and Kidney Diseases.
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6
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Tiburski C, Boje A, Nilsson S, Say Z, Fritzsche J, Ström H, Hellman A, Langhammer C. Light-Off in Plasmon-Mediated Photocatalysis. ACS Nano 2021; 15:11535-11542. [PMID: 34156229 PMCID: PMC8320230 DOI: 10.1021/acsnano.1c01537] [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] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Accepted: 06/15/2021] [Indexed: 05/30/2023]
Abstract
In plasmon-mediated photocatalysis it is of critical importance to differentiate light-induced catalytic reaction rate enhancement channels, which include near-field effects, direct hot carrier injection, and photothermal catalyst heating. In particular, the discrimination of photothermal and hot electron channels is experimentally challenging, and their role is under keen debate. Here we demonstrate using the example of CO oxidation over nanofabricated neat Pd and Au50Pd50 alloy catalysts, how photothermal rate enhancement differs by up to 3 orders of magnitude for the same photon flux, and how this effect is controlled solely by the position of catalyst operation along the light-off curve measured in the dark. This highlights that small fluctuations in reactor temperature or temperature gradients across a sample may dramatically impact global and local photothermal rate enhancement, respectively, and thus control both the balance between different rate enhancement mechanisms and the way strategies to efficiently distinguish between them should be devised.
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Affiliation(s)
- Christopher Tiburski
- Department
of Physics, Chalmers University of Technology, 412 96 Göteborg, Sweden
| | - Astrid Boje
- Department
of Physics, Chalmers University of Technology, 412 96 Göteborg, Sweden
| | - Sara Nilsson
- Department
of Physics, Chalmers University of Technology, 412 96 Göteborg, Sweden
| | - Zafer Say
- Department
of Physics, Chalmers University of Technology, 412 96 Göteborg, Sweden
| | - Joachim Fritzsche
- Department
of Physics, Chalmers University of Technology, 412 96 Göteborg, Sweden
| | - Henrik Ström
- Department
of Mechanics and Maritime Sciences, Chalmers
University of Technology, 412 96 Göteborg, Sweden
| | - Anders Hellman
- Department
of Physics, Chalmers University of Technology, 412 96 Göteborg, Sweden
| | - Christoph Langhammer
- Department
of Physics, Chalmers University of Technology, 412 96 Göteborg, Sweden
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Valter M, Santos ECD, Pettersson LGM, Hellman A. Selectivity of the First Two Glycerol Dehydrogenation Steps Determined Using Scaling Relationships. ACS Catal 2021. [DOI: 10.1021/acscatal.0c04186] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Mikael Valter
- Department of Physics, Chalmers University of Technology, SE-412 96 Göteborg, Sweden
| | | | | | - Anders Hellman
- Department of Physics and the Competence Centre for Catalysis, Chalmers University of Technology, SE-412 96 Göteborg, Sweden
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8
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Fant M, Ångqvist M, Hellman A, Erhart P. To Every Rule There is an Exception: A Rational Extension of Loewenstein's Rule. Angew Chem Int Ed Engl 2021; 60:5132-5135. [PMID: 33315307 PMCID: PMC7986852 DOI: 10.1002/anie.202013256] [Citation(s) in RCA: 4] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Revised: 12/03/2020] [Indexed: 11/07/2022]
Abstract
Loewenstein's rule, which states that Al-O-Al motifs are energetically unstable, is fundamental to the understanding and design of zeolites. Here, using a combination of electronic structure calculations and lattice models, we show under which circumstances this rule becomes invalid and how it can be rationally extended using the chabasite framework for demonstration.
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Affiliation(s)
- Magnus Fant
- Department of Physics, Chalmers University of Technology, Gothenburg, Sweden
| | - Mattias Ångqvist
- Department of Physics, Chalmers University of Technology, Gothenburg, Sweden
| | - Anders Hellman
- Department of Physics and Competence Centre for Catalysis, Chalmers University of Technology, Gothenburg, Sweden
| | - Paul Erhart
- Department of Physics, Chalmers University of Technology, Gothenburg, Sweden
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9
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Fant M, Ångqvist M, Hellman A, Erhart P. To Every Rule There is an Exception: A Rational Extension of Loewenstein's Rule. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202013256] [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)
- Magnus Fant
- Department of Physics Chalmers University of Technology Gothenburg Sweden
| | - Mattias Ångqvist
- Department of Physics Chalmers University of Technology Gothenburg Sweden
| | - Anders Hellman
- Department of Physics and Competence Centre for Catalysis Chalmers University of Technology Gothenburg Sweden
| | - Paul Erhart
- Department of Physics Chalmers University of Technology Gothenburg Sweden
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10
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Singh AP, Wang RB, Tossi C, Tittonen I, Wickman B, Hellman A. Hydrogen induced interface engineering in Fe 2O 3-TiO 2 heterostructures for efficient charge separation for solar-driven water oxidation in photoelectrochemical cells. RSC Adv 2021; 11:4297-4307. [PMID: 35424412 PMCID: PMC8694353 DOI: 10.1039/d0ra09655e] [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] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Accepted: 01/13/2021] [Indexed: 11/21/2022] Open
Abstract
Semiconductor heterostructure junctions are known to improve the water oxidation performance in photoelectrochemical (PEC) cells. Depending on the semiconductor materials involved, different kinds of junctions can appear, for instance, type II band alignment where the conduction and valence bands of the semiconductor materials are staggered with respect to each other. This band alignment allows for a charge separation of the photogenerated electron-hole pairs, where the holes will go from low-to-high valance band levels and vice versa for the electrons. For this reason, interface engineering has attracted intensive attention in recent years. In this work, a simplified model of the Fe2O3-TiO2 heterostructure was investigated via first-principles calculations. The results show that Fe2O3-TiO2 produces a type I band alignment in the heterojunction, which is detrimental to the water oxidation reaction. However, the results also show that interstitial hydrogens are energetically allowed in TiO2 and that they introduce states above the valance band, which can assist in the transfer of holes through the TiO2 layer. In response, well-defined planar Fe2O3-TiO2 heterostructures were manufactured, and measurements confirm the formation of a type I band alignment in the case of Fe2O3-TiO2, with very low photocurrent density as a result. However, once TiO2 was subjected to hydrogen treatment, there was a nine times higher photocurrent density at 1.50 V vs. the reversible hydrogen electrode under 1 sun illumination as compared to the original heterostructured photoanode. Via optical absorption, XPS analysis, and (photo)electrochemical measurements, it is clear that hydrogen treated TiO2 results in a type II band alignment in the Fe2O3-H:TiO2 heterostructure. This work is an example of how hydrogen doping in TiO2 can tailor the band alignment in TiO2-Fe2O3 heterostructures. As such, it provides valuable insights for the further development of similar material combinations.
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Affiliation(s)
- Aadesh P Singh
- Department of Electronics and Nanoengineering, School of Electrical Engineering, Aalto University P.O. Box 13500 00076 Aalto Finland
| | - Richard Baochang Wang
- Division of Chemical Physics, Department of Physics, Chalmers University of Technology SE-412 96 Göteborg Sweden +46 31 772 5611
| | - Camilla Tossi
- Department of Electronics and Nanoengineering, School of Electrical Engineering, Aalto University P.O. Box 13500 00076 Aalto Finland
| | - Ilkka Tittonen
- Department of Electronics and Nanoengineering, School of Electrical Engineering, Aalto University P.O. Box 13500 00076 Aalto Finland
| | - Björn Wickman
- Division of Chemical Physics, Department of Physics, Chalmers University of Technology SE-412 96 Göteborg Sweden +46 31 772 5611
| | - Anders Hellman
- Division of Chemical Physics, Department of Physics, Chalmers University of Technology SE-412 96 Göteborg Sweden +46 31 772 5611
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11
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Boje A, Taifan WE, Ström H, Bučko T, Baltrusaitis J, Hellman A. First-principles-informed energy span and microkinetic analysis of ethanol catalytic conversion to 1,3-butadiene on MgO. Catal Sci Technol 2021. [DOI: 10.1039/d1cy00419k] [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
First-principles-informed models elucidate the impact of energetic and kinetic limitations on selectivity and activity of ethanol conversion to 1,3-butadiene.
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Affiliation(s)
- Astrid Boje
- Department of Physics, Chalmers University of Technology, 412 96 Göteborg, Sweden
| | - William E. Taifan
- Department of Chemical and Biomolecular Engineering, Lehigh University, B336 Iacocca Hall, 111 Research Drive, Bethlehem, PA 18015, USA
| | - Henrik Ström
- Department of Mechanics and Maritime Sciences, Chalmers University of Technology, 412 96 Göteborg, Sweden
| | - Tomáš Bučko
- Department of Physical and Theoretical Chemistry, Faculty of Natural Sciences, Comenius University in Bratislava, Ilkovičova 6, SK-84215, Bratislava, Slovak Republic
- Institute of Inorganic Chemistry, Slovak Academy of Sciences, Dúbravská cesta 9, SK-84236 Bratislava, Slovak Republic
| | - Jonas Baltrusaitis
- Department of Chemical and Biomolecular Engineering, Lehigh University, B336 Iacocca Hall, 111 Research Drive, Bethlehem, PA 18015, USA
| | - Anders Hellman
- Department of Physics, Chalmers University of Technology, 412 96 Göteborg, Sweden
- Competence Centre for Catalysis, Chalmers University of Technology, 412 96 Göteborg, Sweden
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12
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Singh AP, Levinsson A, Iandolo B, Oksanen J, Hellman A, Wickman B. Improved water oxidation performance of ultra-thin planar hematite photoanode: Synergistic effect of In/Sn doping and an overlayer of metal oxyhydroxides. J Photochem Photobiol A Chem 2020. [DOI: 10.1016/j.jphotochem.2020.112781] [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: 10/23/2022]
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13
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Albinsson D, Boje A, Nilsson S, Tiburski C, Hellman A, Ström H, Langhammer C. Copper catalysis at operando conditions-bridging the gap between single nanoparticle probing and catalyst-bed-averaging. Nat Commun 2020; 11:4832. [PMID: 32973158 PMCID: PMC7518423 DOI: 10.1038/s41467-020-18623-1] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [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: 05/14/2020] [Accepted: 08/26/2020] [Indexed: 12/28/2022] Open
Abstract
In catalysis, nanoparticles enable chemical transformations and their structural and chemical fingerprints control activity. To develop understanding of such fingerprints, methods studying catalysts at realistic conditions have proven instrumental. Normally, these methods either probe the catalyst bed with low spatial resolution, thereby averaging out single particle characteristics, or probe an extremely small fraction only, thereby effectively ignoring most of the catalyst. Here, we bridge the gap between these two extremes by introducing highly multiplexed single particle plasmonic nanoimaging of model catalyst beds comprising 1000 nanoparticles, which are integrated in a nanoreactor platform that enables online mass spectroscopy activity measurements. Using the example of CO oxidation over Cu, we reveal how highly local spatial variations in catalyst state dynamics are responsible for contradicting information about catalyst active phase found in the literature, and identify that both surface and bulk oxidation state of a Cu nanoparticle catalyst dynamically mediate its activity.
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Affiliation(s)
- David Albinsson
- Department of Physics, Chalmers University of Technology, 412 96, Göteborg, Sweden
| | - Astrid Boje
- Department of Physics, Chalmers University of Technology, 412 96, Göteborg, Sweden
| | - Sara Nilsson
- Department of Physics, Chalmers University of Technology, 412 96, Göteborg, Sweden
| | - Christopher Tiburski
- Department of Physics, Chalmers University of Technology, 412 96, Göteborg, Sweden
| | - Anders Hellman
- Department of Physics, Chalmers University of Technology, 412 96, Göteborg, Sweden
- Competence Centre for Catalysis, Chalmers University of Technology, 412 96, Göteborg, Sweden
| | - Henrik Ström
- Department of Mechanics and Maritime Sciences, Chalmers University of Technology, 412 96, Göteborg, Sweden
| | - Christoph Langhammer
- Department of Physics, Chalmers University of Technology, 412 96, Göteborg, Sweden.
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14
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Singh AP, Tossi C, Tittonen I, Hellman A, Wickman B. Synergies of co-doping in ultra-thin hematite photoanodes for solar water oxidation: In and Ti as representative case. RSC Adv 2020; 10:33307-33316. [PMID: 35515023 PMCID: PMC9056703 DOI: 10.1039/d0ra04576d] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [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: 05/23/2020] [Accepted: 08/11/2020] [Indexed: 12/03/2022] Open
Abstract
Solar energy induced water splitting in photoelectrochemical (PEC) cells is one of the most sustainable ways of hydrogen production. The challenge is to develop corrosion resistant and chemically stable semiconductors that absorb sunlight in the visible region and, at the same time, have the band edges matching with the redox level of water. In this work, hematite (α-Fe2O3) thin films were prepared onto an indium-doped tin oxide (ITO; In:SnO2) substrate by e-beam evaporation of Fe, followed by air annealing at two different temperatures: 350 and 500 °C. The samples annealed at 500 °C show an in situ diffusion of indium from the ITO substrate to the surface of α-Fe2O3, where it acts as a dopant and enhances the photoelectrochemical properties of hematite. Structural, optical, chemical and photoelectrochemical analysis reveal that the diffusion of In at 500 °C enhances the optical absorption, increases the electrode–electrolyte contact area by changing the surface topology, improves the carrier concentration and shifts the flat band potential in the cathodic direction. Further enhancement in photocurrent density was observed by ex situ diffusion of Ti, deposited in the form of nanodisks, from the top surface to the bulk. The in situ In diffused α-Fe2O3 photoanode exhibits an improved photoelectrochemical performance, with a photocurrent density of 145 μA cm−2 at 1.23 VRHE, compared to 37 μA cm−2 for the photoanode prepared at 350 °C; it also decreases the photocurrent onset potential from 1.13 V to 1.09 V. However, the In/Ti co-doped sample exhibits an even higher photocurrent density of 290 μA cm−2 at 1.23 VRHE and the photocurrent onset potential decreases to 0.93 VRHE, which is attributed to the additional doping and to the surface becoming more favorable to charge separation. Solar energy induced water splitting in photoelectrochemical (PEC) cells is one of the most sustainable ways of hydrogen production. In this work, hematite (α-Fe2O3) thin film were modified by In3+ and Ti4+ co-doping for enhanced PEC performance.![]()
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Affiliation(s)
- Aadesh P Singh
- Division of Chemical Physics, Department of Physics, Chalmers University of Technology SE-412 96 Göteborg Sweden +46 31 772 51 79.,Engineered Nanosystems Group, School of Science, Aalto University P. O. Box 13500 00076 Aalto Finland
| | - Camilla Tossi
- Department of Electronics and Nanoengineering, School of Electrical Engineering, Aalto University P. O. Box 13500 00076 Aalto Finland
| | - Ilkka Tittonen
- Department of Electronics and Nanoengineering, School of Electrical Engineering, Aalto University P. O. Box 13500 00076 Aalto Finland
| | - Anders Hellman
- Division of Chemical Physics, Department of Physics, Chalmers University of Technology SE-412 96 Göteborg Sweden +46 31 772 51 79
| | - Björn Wickman
- Division of Chemical Physics, Department of Physics, Chalmers University of Technology SE-412 96 Göteborg Sweden +46 31 772 51 79
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15
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Wang X, Arvidsson AA, Skoglundh M, Hellman A, Carlsson PA. Desorption products during linear heating of copper zeolites with pre-adsorbed methanol. Phys Chem Chem Phys 2020; 22:6809-6817. [DOI: 10.1039/c9cp05479k] [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: 01/22/2023]
Abstract
Study of desorption products from Cu-zeolites (MFI and CHA) during methanol-TPD using a chemical flow reactor with a gas phase FTIR spectrometer.
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Affiliation(s)
- Xueting Wang
- Department of Chemistry and Chemical Engineering
- Chalmers University of Technology
- 412 96 Gothenburg
- Sweden
- Competence Centre for Catalysis
| | - Adam A. Arvidsson
- Competence Centre for Catalysis
- Chalmers University of Technology
- 412 96 Gothenburg
- Sweden
- Department of Physics
| | - Magnus Skoglundh
- Department of Chemistry and Chemical Engineering
- Chalmers University of Technology
- 412 96 Gothenburg
- Sweden
- Competence Centre for Catalysis
| | - Anders Hellman
- Competence Centre for Catalysis
- Chalmers University of Technology
- 412 96 Gothenburg
- Sweden
- Department of Physics
| | - Per-Anders Carlsson
- Department of Chemistry and Chemical Engineering
- Chalmers University of Technology
- 412 96 Gothenburg
- Sweden
- Competence Centre for Catalysis
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16
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Huš M, Grilc M, Pavlišič A, Likozar B, Hellman A. Multiscale modelling from quantum level to reactor scale: An example of ethylene epoxidation on silver catalysts. Catal Today 2019. [DOI: 10.1016/j.cattod.2019.05.022] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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17
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Nugroho FAA, Darmadi I, Cusinato L, Susarrey-Arce A, Schreuders H, Bannenberg LJ, da Silva Fanta AB, Kadkhodazadeh S, Wagner JB, Antosiewicz TJ, Hellman A, Zhdanov VP, Dam B, Langhammer C. Metal-polymer hybrid nanomaterials for plasmonic ultrafast hydrogen detection. Nat Mater 2019; 18:489-495. [PMID: 30936481 DOI: 10.1038/s41563-019-0325-4] [Citation(s) in RCA: 52] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2018] [Accepted: 02/21/2019] [Indexed: 05/18/2023]
Abstract
Hydrogen-air mixtures are highly flammable. Hydrogen sensors are therefore of paramount importance for timely leak detection during handling. However, existing solutions do not meet the stringent performance targets set by stakeholders, while deactivation due to poisoning, for example by carbon monoxide, is a widely unsolved problem. Here we present a plasmonic metal-polymer hybrid nanomaterial concept, where the polymer coating reduces the apparent activation energy for hydrogen transport into and out of the plasmonic nanoparticles, while deactivation resistance is provided via a tailored tandem polymer membrane. In concert with an optimized volume-to-surface ratio of the signal transducer uniquely offered by nanoparticles, this enables subsecond sensor response times. Simultaneously, hydrogen sorption hysteresis is suppressed, sensor limit of detection is enhanced, and sensor operation in demanding chemical environments is enabled, without signs of long-term deactivation. In a wider perspective, our work suggests strategies for next-generation optical gas sensors with functionalities optimized by hybrid material engineering.
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Affiliation(s)
- Ferry A A Nugroho
- Department of Physics, Chalmers University of Technology, Göteborg, Sweden.
| | - Iwan Darmadi
- Department of Physics, Chalmers University of Technology, Göteborg, Sweden
| | - Lucy Cusinato
- Department of Physics, Chalmers University of Technology, Göteborg, Sweden
| | | | - Herman Schreuders
- Department of Chemical Engineering, Delft University of Technology, Delft, the Netherlands
| | - Lars J Bannenberg
- Department of Chemical Engineering, Delft University of Technology, Delft, the Netherlands
| | | | - Shima Kadkhodazadeh
- Center for Electron Nanoscopy, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Jakob B Wagner
- Center for Electron Nanoscopy, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Tomasz J Antosiewicz
- Department of Physics, Chalmers University of Technology, Göteborg, Sweden
- Faculty of Physics, University of Warsaw, Warsaw, Poland
| | - Anders Hellman
- Department of Physics, Chalmers University of Technology, Göteborg, Sweden
| | - Vladimir P Zhdanov
- Department of Physics, Chalmers University of Technology, Göteborg, Sweden
- Boreskov Institute of Catalysis, Russian Academy of Sciences, Novosibirsk, Russia
| | - Bernard Dam
- Department of Chemical Engineering, Delft University of Technology, Delft, the Netherlands
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18
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Arvidsson AA, Taifan W, Hellman A, Baltrusaitis J. First-principles microkinetic study of methane and hydrogen sulfide catalytic conversion to methanethiol/dimethyl sulfide on Mo6S8 clusters: activity/selectivity of different promoters. Catal Sci Technol 2019. [DOI: 10.1039/c9cy00375d] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [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
A large fraction of the global natural gas reserves is in the form of sour gas, i.e. contains hydrogen sulfide (H2S) and carbon dioxide (CO2), and needs to be sweetened before utilization.
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Affiliation(s)
- Adam A. Arvidsson
- Department of Physics
- Chalmers University of Technology
- 412 96 Gothenburg
- Sweden
| | - William Taifan
- Department of Chemical and Biomolecular Engineering
- Lehigh University
- Bethlehem
- USA
| | - Anders Hellman
- Department of Physics
- Chalmers University of Technology
- 412 96 Gothenburg
- Sweden
| | - Jonas Baltrusaitis
- Department of Chemical and Biomolecular Engineering
- Lehigh University
- Bethlehem
- USA
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19
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Huš M, Hellman A. Ethylene Epoxidation on Ag(100), Ag(110), and Ag(111): A Joint Ab Initio and Kinetic Monte Carlo Study and Comparison with Experiments. ACS Catal 2018. [DOI: 10.1021/acscatal.8b04512] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [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)
- Matej Huš
- Chalmers University of Technology, Department of Physics, Fysikgränd 3, SE-41296 Gothenburg, Sweden
- National Institute of Chemistry, Department of Catalysis and Chemical Reaction Engineering, Hajdrihova 19, SI-1000 Ljubljana, Slovenia
| | - Anders Hellman
- Chalmers University of Technology, Department of Physics, Fysikgränd 3, SE-41296 Gothenburg, Sweden
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20
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Hagman B, Posada-Borbón A, Schaefer A, Shipilin M, Zhang C, Merte LR, Hellman A, Lundgren E, Grönbeck H, Gustafson J. Steps Control the Dissociation of CO 2 on Cu(100). J Am Chem Soc 2018; 140:12974-12979. [PMID: 30226048 DOI: 10.1021/jacs.8b07906] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
CO2 reduction reactions, which provide one route to limit the emission of this greenhouse gas, are commonly performed over Cu-based catalysts. Here, we use ambient pressure X-ray photoelectron spectroscopy together with density functional theory to obtain an atomistic understanding of the dissociative adsorption of CO2 on Cu(100). We find that the process is dominated by the presence of steps, which promote both a lowering of the dissociation barrier and an efficient separation between adsorbed O and CO, reducing the probability for recombination. The identification of steps as sites for efficient CO2 dissociation provides an understanding that can be used in the design of future CO2 reduction catalysts.
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Affiliation(s)
- Benjamin Hagman
- Synchrotron Radiation Research , Lund University , Box 118, 221 00 Lund , Sweden
| | | | | | - Mikhail Shipilin
- Department of Physics, AlbaNova University Center , Stockholm University , 106 91 Stockholm , Sweden
| | - Chu Zhang
- Synchrotron Radiation Research , Lund University , Box 118, 221 00 Lund , Sweden
| | - Lindsay R Merte
- Department of Materials Science and Applied Mathematics , Malmö University , 205 06 Malmö , Sweden
| | | | - Edvin Lundgren
- Synchrotron Radiation Research , Lund University , Box 118, 221 00 Lund , Sweden
| | | | - Johan Gustafson
- Synchrotron Radiation Research , Lund University , Box 118, 221 00 Lund , Sweden
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21
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Wang RB, Hellman A. Surface terminations of hematite (α-Fe 2O 3) exposed to oxygen, hydrogen, or water: dependence on the density functional theory methodology. J Phys Condens Matter 2018; 30:275002. [PMID: 29790856 DOI: 10.1088/1361-648x/aac743] [Citation(s) in RCA: 6] [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: 06/08/2023]
Abstract
Hematite (α-Fe2O3) is the most stable and abundant iron oxide in nature, and is used in many important environmental and industrial technologies, such as waste-water treatment, gas sensors, and photoelectrocatalysis. A clear understanding of the structure, composition, and chemistry of the hematite surface is crucial for improving its function in these technologies. Here we employ density functional theory (DFT) together with the DFT+U approach using semi-local functionals, as well as hybrid functionals, to study the structure, stability, and electronic properties of the (0 0 0 1) surface exposed to oxygen, hydrogen, or water. The use of hybrid functionals allow for a description of strong correlation without the need for atom-specific empirical parameters (i.e. U). However, we find that PBE+U, and in part also PBE, give similar results as the hybrid functional HSE(12%) in terms of structure optimization. When it comes to stability, work function, as well as electronic structure, the results are sensitive to the choice of functionals, but we cannot judge which level of functional is most appropriate due to the lack of experimental observations.
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Affiliation(s)
- Richard B Wang
- Department of Physics, Chalmers University of Technology, SE-412 96 Göteborg, Sweden
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22
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Affiliation(s)
- Richard B. Wang
- Department of Physics, Chalmers University of Technology, SE-412 96 Göteborg, Sweden
| | - Anders Hellman
- Department of Physics, Chalmers University of Technology, SE-412 96 Göteborg, Sweden
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23
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Wickman B, Bastos Fanta A, Burrows A, Hellman A, Wagner JB, Iandolo B. Iron Oxide Films Prepared by Rapid Thermal Processing for Solar Energy Conversion. Sci Rep 2017; 7:40500. [PMID: 28091573 PMCID: PMC5238422 DOI: 10.1038/srep40500] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [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: 10/06/2016] [Accepted: 12/07/2016] [Indexed: 11/25/2022] Open
Abstract
Hematite is a promising and extensively investigated material for various photoelectrochemical (PEC) processes for energy conversion and storage, in particular for oxidation reactions. Thermal treatments during synthesis of hematite are found to affect the performance of hematite electrodes considerably. Herein, we present hematite thin films fabricated via one-step oxidation of Fe by rapid thermal processing (RTP). In particular, we investigate the effect of oxidation temperature on the PEC properties of hematite. Films prepared at 750 °C show the highest activity towards water oxidation. These films show the largest average grain size and the highest charge carrier density, as determined from electron microscopy and impedance spectroscopy analysis. We believe that the fast processing enabled by RTP makes this technique a preferred method for investigation of novel materials and architectures, potentially also on nanostructured electrodes, where retaining high surface area is crucial to maximize performance.
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Affiliation(s)
- B. Wickman
- Department of Physics, Chalmers University of Technology, SE-42196 Göteborg, Sweden
| | - A. Bastos Fanta
- Center for electron nanoscopy, Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark
| | - A. Burrows
- Center for electron nanoscopy, Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark
| | - A. Hellman
- Department of Physics, Chalmers University of Technology, SE-42196 Göteborg, Sweden
| | - J. B. Wagner
- Center for electron nanoscopy, Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark
| | - B. Iandolo
- Center for electron nanoscopy, Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark
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24
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Taifan W, Arvidsson AA, Nelson E, Hellman A, Baltrusaitis J. CH4 and H2S reforming to CH3SH and H2 catalyzed by metal-promoted Mo6S8 clusters: a first-principles micro-kinetic study. Catal Sci Technol 2017. [DOI: 10.1039/c7cy00857k] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [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
Density Functional Theory (DFT) and microkinetic modelling of CH4 and H2S reactions to form CH3SH and H2 as a first step in elucidating complex pathways in oxygen-free sour gas reforming was performed.
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Affiliation(s)
- William Taifan
- Department of Chemical and Biomolecular Engineering
- Lehigh University
- Bethlehem
- USA
| | - Adam A. Arvidsson
- Department of Physics
- Chalmers University of Technology
- SE-421 96 Göteborg
- Sweden
| | - Eric Nelson
- Department of Chemical and Biomolecular Engineering
- Lehigh University
- Bethlehem
- USA
| | - Anders Hellman
- Department of Physics
- Chalmers University of Technology
- SE-421 96 Göteborg
- Sweden
| | - Jonas Baltrusaitis
- Department of Chemical and Biomolecular Engineering
- Lehigh University
- Bethlehem
- USA
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25
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Arvidsson AA, Zhdanov VP, Carlsson PA, Grönbeck H, Hellman A. Metal dimer sites in ZSM-5 zeolite for methane-to-methanol conversion from first-principles kinetic modelling: is the [Cu–O–Cu]2+motif relevant for Ni, Co, Fe, Ag, and Au? Catal Sci Technol 2017. [DOI: 10.1039/c6cy02521h] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [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
Reaction energy landscapes for the direct conversion of methane to methanol over ZSM-5 for Cu, Ni, Co and Fe dimer sites.
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Affiliation(s)
- Adam A. Arvidsson
- Competence Centre for Catalysis
- Department of Physics
- Chemistry and Chemical Engineering
- Chalmers University of Technology
- 412 96 Gothenburg
| | - Vladimir P. Zhdanov
- Competence Centre for Catalysis
- Department of Physics
- Chemistry and Chemical Engineering
- Chalmers University of Technology
- 412 96 Gothenburg
| | - Per-Anders Carlsson
- Competence Centre for Catalysis
- Department of Physics
- Chemistry and Chemical Engineering
- Chalmers University of Technology
- 412 96 Gothenburg
| | - Henrik Grönbeck
- Competence Centre for Catalysis
- Department of Physics
- Chemistry and Chemical Engineering
- Chalmers University of Technology
- 412 96 Gothenburg
| | - Anders Hellman
- Competence Centre for Catalysis
- Department of Physics
- Chemistry and Chemical Engineering
- Chalmers University of Technology
- 412 96 Gothenburg
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26
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Affiliation(s)
- S S Kalter
- Microbiology and Infectious Diseases, Southwest Foundation for Research and Education, PO Box 28147, San Antonio, Texas, USA
| | - R L Heberling
- Microbiology and Infectious Diseases, Southwest Foundation for Research and Education, PO Box 28147, San Antonio, Texas, USA
| | - A Hellman
- National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20014, USA
| | - G J Todaro
- National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20014, USA
| | - M Panigel
- Biology of Reproduction, University of Paris, France
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27
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Frost R, Wadell C, Hellman A, Molander S, Svedhem S, Persson M, Langhammer C. Core–Shell Nanoplasmonic Sensing for Characterization of Biocorona Formation and Nanoparticle Surface Interactions. ACS Sens 2016. [DOI: 10.1021/acssensors.6b00156] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Affiliation(s)
| | | | | | | | | | - Michael Persson
- Akzo Nobel Pulp and Performance Chemicals, SE-445 80 Bohus, Sweden
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28
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Adams EC, Merte LR, Hellman A, Skoglundh M, Gustafson J, Bendixen EC, Gabrielsson P, Bertram F, Evertsson J, Zhang C, Carlson S, Carlsson PA. The structure-function relationship for alumina supported platinum during the formation of ammonia from nitrogen oxide and hydrogen in the presence of oxygen. Phys Chem Chem Phys 2016; 18:10850-5. [PMID: 27039829 DOI: 10.1039/c5cp07624b] [Citation(s) in RCA: 2] [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: 12/27/2022]
Abstract
We study the structure-function relationship of alumina supported platinum during the formation of ammonia from nitrogen oxide and dihydrogen by employing in situ X-ray absorption and Fourier transform infrared spectroscopy. Particular focus has been directed towards the effect of oxygen on the reaction as a model system for emerging technologies for passive selective catalytic reduction of nitrogen oxides. The suppressed formation of ammonia observed as the feed becomes net-oxidizing is accompanied by a considerable increase in the oxidation state of platinum as well as the formation of surface nitrates and the loss of NH-containing surface species. In the presence of (excess) oxygen, the ammonia formation is proposed to be limited by weak interaction between nitrogen oxide and the oxidized platinum surface. This leads to a slow dissociation rate of nitrogen oxide and thus low abundance of the atomic nitrogen surface species that can react with the adsorbed hydrogen species. In this case the consumption of hydrogen through the competing water formation reaction and decomposition/oxidation of ammonia are of less importance for the net ammonia formation.
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Affiliation(s)
- Emma Catherine Adams
- Competence Centre for Catalysis, Chalmers University of Technology, SE-412 96 Göteborg, Sweden.
| | - Lindsay Richard Merte
- Division of Synchrotron Radiation Research, Lund University, Box 118, SE-221 100 Lund, Sweden
| | - Anders Hellman
- Competence Centre for Catalysis, Chalmers University of Technology, SE-412 96 Göteborg, Sweden.
| | - Magnus Skoglundh
- Competence Centre for Catalysis, Chalmers University of Technology, SE-412 96 Göteborg, Sweden.
| | - Johan Gustafson
- Division of Synchrotron Radiation Research, Lund University, Box 118, SE-221 100 Lund, Sweden
| | | | | | - Florian Bertram
- Division of Synchrotron Radiation Research, Lund University, Box 118, SE-221 100 Lund, Sweden
| | - Jonas Evertsson
- Division of Synchrotron Radiation Research, Lund University, Box 118, SE-221 100 Lund, Sweden
| | - Chu Zhang
- Division of Synchrotron Radiation Research, Lund University, Box 118, SE-221 100 Lund, Sweden
| | - Stefan Carlson
- Division of Synchrotron Radiation Research, Lund University, Box 118, SE-221 100 Lund, Sweden
| | - Per-Anders Carlsson
- Competence Centre for Catalysis, Chalmers University of Technology, SE-412 96 Göteborg, Sweden.
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29
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Iandolo B, Wickman B, Svensson E, Paulsson D, Hellman A. Tailoring Charge Recombination in Photoelectrodes Using Oxide Nanostructures. Nano Lett 2016; 16:2381-2386. [PMID: 26978576 DOI: 10.1021/acs.nanolett.5b05154] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Optimizing semiconductor devices for solar energy conversion requires an explicit control of the recombination of photogenerated electron-hole pairs. Here we show how the recombination of charge carriers can be controlled in semiconductor thin films by surface patterning with oxide nanodisks. The control mechanism relies on the formation of dipole-like electric fields at the interface that, depending on the field direction, attract or repel minority carriers from underneath the disks. The charge recombination rate can be controlled through the choice of oxide material and the surface coverage of nanodisks. We provide proof-of-principle demonstration of this approach by patterning the surface of Fe2O3, one of the most studied semiconductors for light-driven water splitting, with TiO2 and Cu2O nanodisks. We expect this method to be generally applicable to a range of semiconductor-based solar energy conversion devices.
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Affiliation(s)
- Beniamino Iandolo
- Department of Physics, Chalmers University of Technology , 412 96 Göteborg, Sweden
- Center for Electron Nanoscopy, Technical University of Denmark , 2800 Kongens Lyngby, Denmark
| | - Björn Wickman
- Department of Physics, Chalmers University of Technology , 412 96 Göteborg, Sweden
| | - Elin Svensson
- Department of Physics, Chalmers University of Technology , 412 96 Göteborg, Sweden
| | - Daniel Paulsson
- Department of Physics, Chalmers University of Technology , 412 96 Göteborg, Sweden
| | - Anders Hellman
- Department of Physics, Chalmers University of Technology , 412 96 Göteborg, Sweden
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30
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Jiao Y, Hellman A, Fang Y, Gao S, Käll M. Schottky barrier formation and band bending revealed by first- principles calculations. Sci Rep 2015; 5:11374. [PMID: 26065401 PMCID: PMC4464327 DOI: 10.1038/srep11374] [Citation(s) in RCA: 64] [Impact Index Per Article: 7.1] [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: 05/10/2015] [Accepted: 05/26/2015] [Indexed: 11/09/2022] Open
Abstract
The formation of a Schottky barrier at the metal-semiconductor interface is widely utilised in semiconductor devices. With the emerging of novel Schottky barrier based nanoelectronics, a further microscopic understanding of this interface is in high demand. Here we provide an atomistic insight into potential barrier formation and band bending by ab initio simulations and model analysis of a prototype Schottky diode, i.e., niobium doped rutile titania in contact with gold (Au/Nb:TiO2). The local Schottky barrier height is found to vary between 0 and 1.26 eV depending on the position of the dopant. The band bending is caused by a dopant induced dipole field between the interface and the dopant site, whereas the pristine Au/TiO2 interface does not show any band bending. These findings open the possibility for atomic scale optimisation of the Schottky barrier and light harvesting in metal-semiconductor nanostructures.
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Affiliation(s)
- Yang Jiao
- Department of Applied Physics, Chalmers University of Technology, Göteborg, SE-412 96, Sweden
| | - Anders Hellman
- Department of Applied Physics, Chalmers University of Technology, Göteborg, SE-412 96, Sweden
| | - Yurui Fang
- Department of Applied Physics, Chalmers University of Technology, Göteborg, SE-412 96, Sweden
| | - Shiwu Gao
- Beijing Computational Science Research Center, Beijing, 100094, China
| | - Mikael Käll
- Department of Applied Physics, Chalmers University of Technology, Göteborg, SE-412 96, Sweden
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Kalter SS, Heberling RL, Helmke RJ, Panigel M, Smith GC, Kraemer DC, Hellman A, Fowler AK, Strickland JE. A comparative study on the presence of C-type viral particles in placentas from primates and other animals. Bibl Haematol 2015:391-401. [PMID: 169817 DOI: 10.1159/000397557] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
C-type particles are found in human, baboon, marmoset, rhesus, patas, and cynomolgus monkeys. A cebus monkey and two chimpanzee placentas have failed thus far to show the presence of these particles. Of the nonprimate tissues examined one mouse and one guinea pig placenta were positive whereas a rabbit placenta was negative. Variations in number of particles present in tissues as well as number of animals of a given species containing particles are noted. The isolation of foamyviruses from placenta cultures makes critical evaluation and interpretation of findings imperative. Several considerations suggest that the presence of foamyviruses is coincidental.
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Adi Harel S, Bossel Ben-Moshe N, Aylon Y, Bublik DR, Moskovits N, Toperoff G, Azaiza D, Biagoni F, Fuchs G, Wilder S, Hellman A, Blandino G, Domany E, Oren M. Reactivation of epigenetically silenced miR-512 and miR-373 sensitizes lung cancer cells to cisplatin and restricts tumor growth. Cell Death Differ 2015; 22:1328-40. [PMID: 25591738 DOI: 10.1038/cdd.2014.221] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2014] [Revised: 11/23/2014] [Accepted: 11/24/2014] [Indexed: 12/19/2022] Open
Abstract
MicroRNAs (miRs) regulate a variety of cellular processes, and their impaired expression is involved in cancer. Silencing of tumor-suppressive miRs in cancer can occur through epigenetic modifications, including DNA methylation and histone deacetylation. We performed comparative miR profiling on cultured lung cancer cells before and after treatment with 5'aza-deoxycytidine plus Trichostatin A to reverse DNA methylation and histone deacetylation, respectively. Several tens of miRs were strongly induced by such 'epigenetic therapy'. Two representatives, miR-512-5p (miR-512) and miR-373, were selected for further analysis. Both miRs were secreted in exosomes. Re-expression of both miRs augmented cisplatin-induced apoptosis and inhibited cell migration; miR-512 also reduced cell proliferation. TEAD4 mRNA was confirmed as a direct target of miR-512; likewise, miR-373 was found to target RelA and PIK3CA mRNA directly. Our results imply that miR-512 and miR-373 exert cell-autonomous and non-autonomous tumor-suppressive effects in lung cancer cells, where their re-expression may benefit epigenetic cancer therapy.
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Affiliation(s)
- S Adi Harel
- Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot 76100, Israel
| | - N Bossel Ben-Moshe
- Department of Physics of Complex Systems, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Y Aylon
- Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot 76100, Israel
| | - D R Bublik
- Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot 76100, Israel
| | - N Moskovits
- Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot 76100, Israel
| | - G Toperoff
- Department of Developmental Biology and Cancer Research, Institute for Medical Research Israel-Canada, Hebrew University-Hadassah Medical School, Jerusalem 91120, Israel
| | - D Azaiza
- Department of Developmental Biology and Cancer Research, Institute for Medical Research Israel-Canada, Hebrew University-Hadassah Medical School, Jerusalem 91120, Israel
| | - F Biagoni
- Translational Oncogenomic Unit, Regina Elena National Cancer Institute, Rome, Italy
| | - G Fuchs
- Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot 76100, Israel
| | - S Wilder
- Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot 76100, Israel
| | - A Hellman
- Department of Developmental Biology and Cancer Research, Institute for Medical Research Israel-Canada, Hebrew University-Hadassah Medical School, Jerusalem 91120, Israel
| | - G Blandino
- Translational Oncogenomic Unit, Regina Elena National Cancer Institute, Rome, Italy
| | - E Domany
- Department of Physics of Complex Systems, Weizmann Institute of Science, Rehovot 76100, Israel
| | - M Oren
- Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot 76100, Israel
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Wettergren K, Hellman A, Cavalca F, Zhdanov VP, Langhammer C. Unravelling the dependence of hydrogen oxidation kinetics on the size of Pt nanoparticles by in operando nanoplasmonic temperature sensing. Nano Lett 2015; 15:574-80. [PMID: 25479190 DOI: 10.1021/nl504042u] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
We use a noninvasive nanoscale optical-temperature measurement method based on localized surface plasmon resonance to investigate the particle size-dependence of the hydrogen oxidation reaction kinetics on model supported Pt nanocatalysts at atmospheric pressure in operando. With decreasing average nanoparticle size from 11 down to 3 nm, the apparent reaction activation energy is found to increase from 0.5 up to 0.8 eV. This effect is attributed to an increase of the fraction of (100)-facet and edge and corner sites and their increasingly important role in the reaction with decreasing particle size.
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Affiliation(s)
- Kristina Wettergren
- Department of Applied Physics and ‡Competence Centre for Catalysis, Chalmers University of Technology , 41296 Göteborg, Sweden
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34
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Iandolo B, Zhang H, Wickman B, Zorić I, Conibeer G, Hellman A. Correlating flat band and onset potentials for solar water splitting on model hematite photoanodes. RSC Adv 2015. [DOI: 10.1039/c5ra10215d] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Increasing oxidation time during fabrication of hematite (Fe2O3) films reduces the amount of grain boundaries, resulting in lower flat band potential and onset potential for water oxidation.
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Affiliation(s)
- Beniamino Iandolo
- Department of Applied Physics
- Chalmers University of Technology
- SE-41296 Göteborg
- Sweden
| | - Haixiang Zhang
- School of Photovoltaic and Renewable Energy Engineering
- University of New South Wales
- Sydney
- Australia
| | - Björn Wickman
- Department of Applied Physics
- Chalmers University of Technology
- SE-41296 Göteborg
- Sweden
| | - Igor Zorić
- Department of Applied Physics
- Chalmers University of Technology
- SE-41296 Göteborg
- Sweden
| | - Gavin Conibeer
- School of Photovoltaic and Renewable Energy Engineering
- University of New South Wales
- Sydney
- Australia
| | - Anders Hellman
- Department of Applied Physics
- Chalmers University of Technology
- SE-41296 Göteborg
- Sweden
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Iandolo B, Hellman A. The Role of Surface States in the Oxygen Evolution Reaction on Hematite. Angew Chem Int Ed Engl 2014; 53:13404-8. [DOI: 10.1002/anie.201406800] [Citation(s) in RCA: 113] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2014] [Revised: 08/25/2014] [Indexed: 11/10/2022]
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Martin NM, Van den Bossche M, Hellman A, Grönbeck H, Hakanoglu C, Gustafson J, Blomberg S, Johansson N, Liu Z, Axnanda S, Weaver JF, Lundgren E. Intrinsic Ligand Effect Governing the Catalytic Activity of Pd Oxide Thin Films. ACS Catal 2014. [DOI: 10.1021/cs5010163] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.6] [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)
- Natalia M. Martin
- Division
of Synchrotron Radiation Research, Lund University, Box 118, SE-221
00 Lund, Sweden
| | - Maxime Van den Bossche
- Competence
Centre for Catalysis and Department of Applied
Physics, Chalmers University of Technology, SE-41296 Göteborg, Sweden
| | - Anders Hellman
- Competence
Centre for Catalysis and Department of Applied
Physics, Chalmers University of Technology, SE-41296 Göteborg, Sweden
| | - Henrik Grönbeck
- Competence
Centre for Catalysis and Department of Applied
Physics, Chalmers University of Technology, SE-41296 Göteborg, Sweden
| | - Can Hakanoglu
- Department
of Chemical Engineering, University of Florida, Gainesville, Florida 32611, United States
| | - Johan Gustafson
- Division
of Synchrotron Radiation Research, Lund University, Box 118, SE-221
00 Lund, Sweden
| | - Sara Blomberg
- Division
of Synchrotron Radiation Research, Lund University, Box 118, SE-221
00 Lund, Sweden
| | - Niclas Johansson
- Division
of Synchrotron Radiation Research, Lund University, Box 118, SE-221
00 Lund, Sweden
| | - Zhi Liu
- Advanced
Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Stephanus Axnanda
- Advanced
Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Jason F. Weaver
- Department
of Chemical Engineering, University of Florida, Gainesville, Florida 32611, United States
| | - Edvin Lundgren
- Division
of Synchrotron Radiation Research, Lund University, Box 118, SE-221
00 Lund, Sweden
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Abstract
A first-principles account of the observed limiting thickness of oxide films formed on aluminum during oxidizing conditions is presented. The results uncover enhanced bonding of oxygen to thin alumina films in contact with metallic aluminum that stems from charge transfer between a reconstructed oxide-metal interface and the adsorbed molecules. The first-principles results are compared with the traditional Cabrera-Mott (CM) model, which is a classical continuum model. Within the CM model, charged surface oxygen species and metal ions generate a (Mott) potential that drives oxidation. An apparent limiting thickness is observed as the oxidation rate decreases rapidly with film growth. The present results support experimental estimates of the Mott potential and film thicknesses. In contrast to the CM model, however, the calculations reveal a real limiting thickness that originates from a diminishing oxygen adsorption energy beyond a certain oxide film thickness.
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Affiliation(s)
- Jakub D Baran
- Department of Applied Physics and Competence Centre for Catalysis, Chalmers University of Technology, SE-412 96 Göteborg, Sweden
| | - Henrik Grönbeck
- Department of Applied Physics and Competence Centre for Catalysis, Chalmers University of Technology, SE-412 96 Göteborg, Sweden
| | - Anders Hellman
- Department of Applied Physics and Competence Centre for Catalysis, Chalmers University of Technology, SE-412 96 Göteborg, Sweden
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West SD, Hellman A, Tawil I, Harding J. Emergent endotracheal tube exchange following acute obstruction of an electromyography monitoring endotracheal tube. Anaesth Intensive Care 2014; 42:271-273. [PMID: 24580403] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
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Baran JD, Grönbeck H, Hellman A. Analysis of Porphyrines as Catalysts for Electrochemical Reduction of O2 and Oxidation of H2O. J Am Chem Soc 2014; 136:1320-6. [DOI: 10.1021/ja4060299] [Citation(s) in RCA: 106] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Jakub D. Baran
- Competence
Centre for Catalysis
and Department of Applied Physics, Chalmers University of Technology, SE-412 96, Göteborg, Sweden
| | - Henrik Grönbeck
- Competence
Centre for Catalysis
and Department of Applied Physics, Chalmers University of Technology, SE-412 96, Göteborg, Sweden
| | - Anders Hellman
- Competence
Centre for Catalysis
and Department of Applied Physics, Chalmers University of Technology, SE-412 96, Göteborg, Sweden
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41
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Iandolo B, Wickman B, Seger B, Chorkendorff I, Zorić I, Hellman A. Faradaic efficiency of O2evolution on metal nanoparticle sensitized hematite photoanodes. Phys Chem Chem Phys 2014; 16:1271-5. [DOI: 10.1039/c3cp54288b] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Baltrusaitis J, Hu YS, McFarland EW, Hellman A. Photoelectrochemical hydrogen production on α-Fe2O3 (0001): insights from theory and experiments. ChemSusChem 2014; 7:162-171. [PMID: 24130006 DOI: 10.1002/cssc.201300715] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2013] [Revised: 08/29/2013] [Indexed: 06/02/2023]
Abstract
The photoelectrochemical (PEC) decomposition of organic compounds in wastewater is investigated by using quantum chemical (DFT) methods to evaluate alternatives to water splitting for the production of renewable and sustainable hydrogen. Methanol is used as a model organic species for the theoretical evaluations of electrolysis on the surface of the widely available semiconductor hematite, α-Fe2 O3 , a widely studied photocatalyst. Three different α-Fe2 O3 surface terminations were investigated, including the predominant surface found in aqueous electrolytes, (OH)3 R. The PEC oxidation of methanol is energetically downhill, producing CO2 and protons. The protons are reduced to hydrogen on the cathode. Experimental PEC measurements were also performed for several polyalcoholic compounds, glycerol, erythritol, and xylitol, on α-Fe2 O3 as the photocatalyst and showed high incident-photon-to-current-efficiencies (IPCE) that were much greater than those of water splitting. Interestingly, high IPCEs were observed for hydrogen production from polyalcohols in the absence of any applied bias, which was not thought to be possible on hematite. These results support the potential application of PEC for hydrogen production by using widely available hematite for the PEC oxidation of selected components of organic wastewater present in large quantities from anthropogenic and industrial sources.
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Affiliation(s)
- Jonas Baltrusaitis
- PhotoCatalytic Synthesis Group, MESA+ Institute for Nanotechnology, Faculty of Science and Technology, University of Twente, Meander 229, P.O. Box 217, 7500 AE Enschede, The Netherlands, Fax: (+31) 53-489-3968; Department of Occupational and Environmental Health, College of Public Health, University of Iowa, Iowa City, IA, 52242 (USA).
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44
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Paz-Borbón LO, Hellman A, Thomas JM, Grönbeck H. Efficient hydrogenation over single-site bimetallic RuSn clusters. Phys Chem Chem Phys 2013; 15:9694-700. [DOI: 10.1039/c3cp51384j] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Kannisto H, Arve K, Pingel T, Hellman A, Härelind H, Eränen K, Olsson E, Skoglundh M, Murzin DY. On the performance of Ag/Al2O3as a HC-SCR catalyst – influence of silver loading, morphology and nature of the reductant. Catal Sci Technol 2013. [DOI: 10.1039/c2cy20594g] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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46
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Iandolo B, Antosiewicz TJ, Hellman A, Zorić I. On the mechanism for nanoplasmonic enhancement of photon to electron conversion in nanoparticle sensitized hematite films. Phys Chem Chem Phys 2013; 15:4947-54. [DOI: 10.1039/c3cp44483j] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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47
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Hellman A, Resta A, Martin NM, Gustafson J, Trinchero A, Carlsson PA, Balmes O, Felici R, van Rijn R, Frenken JWM, Andersen JN, Lundgren E, Grönbeck H. The Active Phase of Palladium during Methane Oxidation. J Phys Chem Lett 2012; 3:678-682. [PMID: 26286272 DOI: 10.1021/jz300069s] [Citation(s) in RCA: 96] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The active phase of Pd during methane oxidation is a long-standing puzzle, which, if solved, could provide routes for design of improved catalysts. Here, density functional theory and in situ surface X-ray diffraction are used to identify and characterize atomic sites yielding high methane conversion. Calculations are performed for methane dissociation over a range of Pd and PdOx surfaces and reveal facile dissociation on either under-coordinated Pd sites in PdO(101) or metallic surfaces. The experiments show unambiguously that high methane conversion requires sufficiently thick PdO(101) films or metallic Pd, in full agreement with the calculations. The established link between high activity and atomic structure enables rational design of improved catalysts.
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Affiliation(s)
- A Hellman
- †Competence Centre for Catalysis, Chalmers University of Technology, SE-412 96, Göteborg, Sweden
| | - A Resta
- ‡ESRF, 6 rue Jules Horowitz -38000 Grenoble, France
| | - N M Martin
- §Division of Synchrotron Radiation Research, Lund University, Box 118, SE-221 00, Sweden
| | - J Gustafson
- §Division of Synchrotron Radiation Research, Lund University, Box 118, SE-221 00, Sweden
| | - A Trinchero
- †Competence Centre for Catalysis, Chalmers University of Technology, SE-412 96, Göteborg, Sweden
| | - P-A Carlsson
- †Competence Centre for Catalysis, Chalmers University of Technology, SE-412 96, Göteborg, Sweden
| | - O Balmes
- ‡ESRF, 6 rue Jules Horowitz -38000 Grenoble, France
| | - R Felici
- ‡ESRF, 6 rue Jules Horowitz -38000 Grenoble, France
| | - R van Rijn
- ‡ESRF, 6 rue Jules Horowitz -38000 Grenoble, France
- ∥Kamerlingh Onnes Laboratory, Leiden University, P.O. Box 9504, 2300 RA Leiden, The Netherlands
| | - J W M Frenken
- ∥Kamerlingh Onnes Laboratory, Leiden University, P.O. Box 9504, 2300 RA Leiden, The Netherlands
| | - J N Andersen
- §Division of Synchrotron Radiation Research, Lund University, Box 118, SE-221 00, Sweden
| | - E Lundgren
- §Division of Synchrotron Radiation Research, Lund University, Box 118, SE-221 00, Sweden
| | - H Grönbeck
- †Competence Centre for Catalysis, Chalmers University of Technology, SE-412 96, Göteborg, Sweden
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49
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Affiliation(s)
- Anders Hellman
- Competence Center for Catalysis and Department of Applied Physics, Chalmers University of Technology, SE-412 96 Göteborg, Sweden
| | - Simon Klacar
- Competence Center for Catalysis and Department of Applied Physics, Chalmers University of Technology, SE-412 96 Göteborg, Sweden
| | - Henrik Grönbeck
- Competence Center for Catalysis and Department of Applied Physics, Chalmers University of Technology, SE-412 96 Göteborg, Sweden
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50
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Vojvodic A, Hellman A, Ruberto C, Lundqvist BI. From electronic structure to catalytic activity: a single descriptor for adsorption and reactivity on transition-metal carbides. Phys Rev Lett 2009; 103:146103. [PMID: 19905584 DOI: 10.1103/physrevlett.103.146103] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2009] [Indexed: 05/28/2023]
Abstract
Adsorption and catalytic properties of the polar (111) surface of transition-metal carbides (TMC's) are investigated by density-functional theory. Atomic and molecular adsorption are rationalized with the concerted-coupling model, in which two types of TMC surface resonances (SR's) play key roles. The transition-metal derived SR is found to be a single measurable descriptor for the adsorption processes, implying that the Brønsted-Evans-Polanyi relation and scaling relations apply. This gives a picture with implications for ligand and vacancy effects and which has a potential for a broad screening procedure for heterogeneous catalysts.
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Affiliation(s)
- A Vojvodic
- Department of Applied Physics, Chalmers University of Technology, SE-412 96 Göteborg, Sweden.
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