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Theoretical investigation of photocatalytic water splitting on surfaces and thin films of perovskite oxynitrides

English title Theoretical investigation of photocatalytic water splitting on surfaces and thin films of perovskite oxynitrides
Applicant Aschauer Ulrich
Number 187185
Funding scheme SNSF Professorships
Research institution Departement für Chemie, Biochemie und Pharmazie Universität Bern
Institution of higher education University of Berne - BE
Main discipline Physical Chemistry
Start/End 01.01.2020 - 31.12.2021
Approved amount 593'393.00
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All Disciplines (3)

Discipline
Physical Chemistry
Inorganic Chemistry
Material Sciences

Keywords (3)

Density functional theory; Oxynitrides; Photocatalysis

Lay Summary (German)

Lead
Oxidmaterialien, die in einer Perowskit-Struktur kristallisieren, weisen aufgrund ihrer strukturellen und chemischen Vielfalt ein grosses Potential für Anwendungen im Bereich der erneuerbaren Energien auf. Für die Wasserstoffgewinnung anhand von Wasserspaltung zeigen speziell Perowskit Oxinitride mit einer Kombination aus Sauerstoff- und Stickstoffanionen experimentell höchst vielversprechende Resultate. Deren Oberflächenstruktur und -chemie, welche für dieses verbesserte Verhalten mitverantwortlich sein muss, wurde im vorhergehenden Projekt etabliert, jedoch bleiben noch offene Fragen in Bezug auf die Materialstabilität und den Effekt der ferroelektrischen Polarisierung zu klären. Dieses Wissen ist unbedingt erforderlich, um den Wirkungsgrad und die Lebensdauer von Oxinitriden bei der Wasserspaltung weiter zu verbessern.
Lay summary
Inhalt und Ziel des Forschungsprojekts

Ziel dieses Forschungsprojekts ist es, mittels quantenmechanischer Berechnungen den Effekt unterschiedlicher Korrosionsschutzschichten auf die Lichtabsorption, den Ladungstransport und die katalytische Aktivität von Perowskit Oxinitrid Lichtabsorbern zu untersuchen. Mittels der gleichen Methoden werden wir auch den unterdrückenden Effekt von oxidativen Adsorbaten auf die ferroelektrische Polarisierung untersuchen, um zu klären ob Ferroelektrizität unter Anwendungsbedingungen in wässriger Lösung zu den bisher im Hochvakuum vorhergesagten Verbesserungen des Wirkungsgrads führen kann.

Wissenschaftlicher und gesellschaftlicher Kontext des Forschungsprojekts

Die theoretischen Arbeiten in diesem Projekt werden in enger Zusammenarbeit mit experimentellen Partnern durchgeführt, was den Transfers des erlangten Grundlagenwissens in die angewandte Wissenschaft und schlussendlich in die Industrie sicherstellt. Es resultieren innovative Materialen, welche aus Sonnenlicht und Wasser effizient Wasserstoffgas erzeugen. Letzteres gilt als vielversprechender Brennstoff zukünftiger Motoren, dessen umweltfreundliche Erzeugung eine Notwendigkeit für dieses alternative Antriebskonzept darstellt. Mit der absehbaren Knappheit fossiler Brennstoffe und deren schädlichen Effekt auf die Umwelt benötigt unsere Gesellschaft dringend erneuerbare und umweltneutrale Energieträger, um die allgemeine Mobilität und Gesundheit zukünftiger Generationen zu garantieren.
Direct link to Lay Summary Last update: 09.10.2019

Responsible applicant and co-applicants

Employees

Publications

Publication
Exploiting Cooperative Catalysis for the On‐Surface Synthesis of Linear Heteroaromatic Polymers via Selective C–H Activation
Liu Xunshan, Matej Adam, Kratky Tim, Mendieta‐Moreno Jesús I., Günther Sebastian, Mutombo Pingo, Decurtins Silvio, Aschauer Ulrich, Repp Jascha, Jelinek Pavel, Liu Shi‐Xia, Patera Laerte L. (2022), Exploiting Cooperative Catalysis for the On‐Surface Synthesis of Linear Heteroaromatic Polymers via Selective C–H Activation, in Angewandte Chemie International Edition, 61(5), e202112798.
Implications of Nonelectrochemical Reaction Steps on the Oxygen Evolution Reaction: Oxygen Dimer Formation on Perovskite Oxide and Oxynitride Surfaces
Vonrüti Nathalie, Rao Reshma, Giordano Livia, Shao-Horn Yang, Aschauer Ulrich (2022), Implications of Nonelectrochemical Reaction Steps on the Oxygen Evolution Reaction: Oxygen Dimer Formation on Perovskite Oxide and Oxynitride Surfaces, in ACS Catalysis, 12(2), 1433-1442.
Importance of surface oxygen vacancies for ultrafast hot carrier relaxation and transport in Cu2O
Ricca Chiara, Grad Lisa, Hengsberger Matthias, Osterwalder Jürg, Aschauer Ulrich (2021), Importance of surface oxygen vacancies for ultrafast hot carrier relaxation and transport in Cu2O, in Physical Review Research, 3(4), 043219-043219.
Effect of tert-butyl groups on electronic communication between redox units in tetrathiafulvalene-tetraazapyrene triads
Zhou Ping, Aschauer Ulrich, Decurtins Silvio, Feurer Thomas, Häner Robert, Liu Shi-Xia (2021), Effect of tert-butyl groups on electronic communication between redox units in tetrathiafulvalene-tetraazapyrene triads, in Chemical communications, 57(96), 12972-12975.
Identifying Reactive Sites and Surface Traps in Chalcopyrite Photocathodes
Liu Yongpeng, Bouri Maria, Yao Liang, Xia Meng, Mensi Mounir, Grätzel Michael, Sivula Kevin, Aschauer Ulrich, Guijarro Néstor (2021), Identifying Reactive Sites and Surface Traps in Chalcopyrite Photocathodes, in Angewandte Chemie (International ed. in English), 60(44), 23651-23655.
Enhancing Oxygen Evolution Reaction Activity by Using Switchable Polarization in Ferroelectric InSnO 2 N
Lan Zhenyun, Småbråten Didrik René, Xiao Chengcheng, Vegge Tejs, Aschauer Ulrich, Castelli Ivano E. (2021), Enhancing Oxygen Evolution Reaction Activity by Using Switchable Polarization in Ferroelectric InSnO 2 N, in ACS Catalysis, 11(20), 12692-12700.
Giant Grüneisen parameter in a superconducting quantum paraelectric
Franklin J., Xu B., Davino D., Mahabir A., Balatsky A. V., Aschauer U., Sochnikov I. (2021), Giant Grüneisen parameter in a superconducting quantum paraelectric, in Physical Review B, 103(21), 214511-214511.
Operando Monitoring the Insulator–Metal Transition of LiCoO2
Flores Eibar, Mozhzhukhina Nataliia, Aschauer Ulrich, Berg Erik J. (2021), Operando Monitoring the Insulator–Metal Transition of LiCoO2, in ACS Applied Materials & Interfaces, 13(19), 22540-22548.
LaTiO2N crystallographic orientation control significantly increases visible-light induced charge extraction
Burns Eric, Aschauer Ulrich, Döbeli Max, Schneider Christof W., Pergolesi Daniele, Lippert Thomas (2020), LaTiO2N crystallographic orientation control significantly increases visible-light induced charge extraction, in Journal of Materials Chemistry A, 8(43), 22867-22873.
Chemical control of photoinduced charge-transfer direction in a tetrathiafulvalene-fused dipyrrolylquinoxaline difluoroborate dyad
Zhou Ping, Aschauer Ulrich, Decurtins Silvio, Feurer Thomas, Häner Robert, Liu Shi-Xia (2020), Chemical control of photoinduced charge-transfer direction in a tetrathiafulvalene-fused dipyrrolylquinoxaline difluoroborate dyad, in Chemical Communications, 56(87), 13421-13424.

Collaboration

Group / person Country
Types of collaboration
Prof. Thomas Lippert, Paul Scherrer Institut Switzerland (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
Prof. Yasushi Hirose / Prof. Tetsuya Hasegawa, University of Tokyo Japan (Asia)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
Prof. Simone Pokrant, Universität Salzburg Austria (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication

Associated projects

Number Title Start Funding scheme
202225 Degradation mechanisms in photoelectrochemical devices 01.05.2022 Sinergia
157615 Theoretical investigation of photocatalytic water splitting on surfaces and thin films of perovskite oxynitrides 01.01.2016 SNSF Professorships

Abstract

The development of alternative renewable energy sources is a highly relevant goal in view of our ever-increasing energy needs and the negative environmental and climate effects of current fossil or nuclear energy sources. Photocatalysis using semiconducting light absorbers is a promising route to convert solar energy into chemical energy stored in the bonds of the formed molecular products. A good photocatalyst has to efficiently absorb solar light, promote separation of the resulting electron and hole charge carriers and provide high catalytic efficiency for the targeted chemical reaction at its surfaces. While many reactions can be photocatalyzed, photocatalytic water splitting and in particular the oxygen evolution (OER) half-reaction is considered to be a good test case to characterize the activity of different semiconductors. Among earth-abundant semiconductor materials that have suitable band gaps, perovskite oxynitrides have emerged as a highly promising class of visible-light absorbers.The preceding project has, for the first time, established the atomic-scale surface structure of these oxynitride materials using density functional theory calculations and highlighted that they have promising catalytic properties. Moreover, we have shown that they can be rendered ferroelectric under compressive epitaxial strain, which will dramatically improve electron-hole separation and, with the switching of the ferroelectric polarization, may enable unprecedented control of reaction pathways. While these results highlight the potential of oxynitrides for photocatalytic applications, they also lead to additional open questions. As such, we have found that the effect of the ferroelectric polarization on the reactivity may be affected by oxidizing adsorbates under photocatalytic application conditions but the relation between polarization, adsorbate coverage and fundamental material parameters is not yet clear. Also, in our calculations, we observed a photo-corrosion instability resulting in N2 or NO evolution under photocatalytic application conditions, which indicates that oxynitrides need to be protected, for example by cocatalysts or protective catalytic coatings. To address these open questions, the goals of this extension project are to: 1) more deeply investigate the effect of ferroelectricity on the catalytic activity of the surface, focusing on application conditions with oxidizing adsorbates; 2) study which materials are suitable as protective and catalytic coatings for oxynitrides and how their thickness affects the stability of the oxynitride and the catalytic activity of the coating.
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