%0 Electronic Article
%A Derelli, Davide
%A Caddeo, Francesco
%A Frank, Kilian
%A Krötzsch, Kilian
%A Ewerhardt, Patrick
%A Krüger, Marco
%A Medicus, Sophie
%A Klemeyer, Lars
%A Skiba, Marvin
%A Gutowski, Olof
%A Dippel, Ann-Christin
%A Parak, Wolfgang J.
%A Nickel, Bert
%A Koziej, Dorota
%T Operando X-ray scattering elucidates the photocorrosion mechanism of CuBi<sub>2</sub>O<sub>4</sub> films
%M PUBDB-2023-05955
%D 2023
%X CuBi2O4 has recently emerged as a promising photocathode for photo-electrochemical (PEC) water splitting. However, its fast degradation under operation currently poses a limit to its application. Here, we report a novel method to study operando the semiconductor-electrolyte interface during PEC operation by surface-sensitive high-energy X-ray scattering. We find that a fast decrease in the generated photocurrents correlates directly with the formation of a metallic Bi phase. We further show that the slower formation of metallic Cu, as well as the dissolution of the electrode in contact with the electrolyte, further affect the CuBi<sub>2</sub>O<sub>4</sub> activity and morphology. Our study provides a comprehensive picture of the degradation mechanisms affecting CuBi<sub>2</sub>O<sub>4</sub> electrodes under operation and poses the methodological basis to investigate the photocorrosion processes affecting a wide range of PEC materials. 
%F PUB:(DE-HGF)25
%9 Preprint
%R 10.26434/chemrxiv-2023-j1q9w
%U https://bib-pubdb1.desy.de/record/594778