The effect of oxygen vacancies in the photoelectrochemical performance of metal oxide photoanodes
Ramón Arcas a, Camilo A. Mesa a, Miguel García-Tecedor a, Maria C. Spadaro b, Jordi Arbiol b, Francisco Fabregat-Santiago a, Sixto Giménez a, Elena Mas-Marzá a
a Institute of Advanced Materials (INAM), Universitat Jaume I, 12006 Castelló, Spain
b Catalan Institute of Nanoscience and Nanotechnology, Carrer del Rosselló, 161, Barcelona, Spain
Materials for Sustainable Development Conference (MATSUS)
Proceedings of Materials for Sustainable Development Conference (MAT-SUS) (NFM22)
#OPCAT - Operando Characterization of Electrocatalytic Interfaces
Barcelona, Spain, 2022 October 24th - 28th
Organizer: Reshma Rao
Contributed talk, Camilo A. Mesa, presentation 078
DOI: https://doi.org/10.29363/nanoge.nfm.2022.078
Publication date: 11th July 2022

Photoelectrocatalysis has emerged as a promising process to store solar energy into fuels and high added-value chemicals to decarbonise the energy and fine chemical sectors. In this process the generation of H2, carbon-based chemicals or NH3 from H+, CO2 and N2 reduction, is usually limited by the oxidation reaction taking place at the photoanode, in particular when using metal-oxide photoanodes. The photoelectrochemical performance of these photoanodes vary depending on their synthetic route and post-synthesis treatment that can lead to crystal defects such as oxygen vacancies. However, the chemical nature of such oxygen vacancies and their role in photoelectrochemical oxidation of water or organic substrates to produce high added-value chemicals is still in debate.

In this talk, I will present a spectroscopic, microscopic and electrochemical analysis of the chemical nature of light-induced oxygen vacancies in one of the most studied photoanodes such as BiVO4. Oxygen vacancies in these BiVO4 photoanodes were produced by light exposure treatments and are associated with the migration of Bi towards the surface forming nanoparticles.[1] Additionally, I will show the role of oxygen vacancies in the photoelectrochemical behaviour of BiVO4, WO3[2] and a-Fe2O3[3] photoanodes and their role in the water oxidation mechanism as example.

he authors thank support from the projects ENE2017-85087-C3-1-R, PID2020-116093RB-C41, PID2020-116093RB -C43 and Network of Excellence CAT&SCALE (RED2018-102459-T), funded by MCIN/ AEI/10.13039/501100011033. University Jaume I (UJI-B2019-20) and Generalitat Valenciana (PROMETEO/2020/028) are also acknowledged for financial support. Serveis Centrals d’Instrumentació Científica from UJI are also acknowledged for SEM, TEM, Raman, and XRD measurements. M.C.S. and J.A. acknowledge funding from Generalitat de Catalunya 2017 SGR 327. ICN2 is supported by the Severo Ochoa program from Spanish MINECO (Grant no. SEV-2017-0706) and is funded by the CERCA Programme/Generalitat de Catalunya. M.C.S. has received funding from the European Union's Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie Grant Agreement no. 754510 (PROBIST) and the Severo Ochoa programme. C.A.M. acknowledges the University Jaume I for the postdoc fellowship POSDOC/2019/20 and Generalitat Valenciana for the APOSTD/2021/251 fellowship. Dr. Beatriz Julián-López and Laura Montañés are also acknowledged for their help with the measurements with the infrared laser beam and some electrodes preparation.

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