The role of oxygen vacancies in water splitting photoanodes

Abstract

Photoelectrochemical water splitting has become one of the most reliable solar-energy conversion technologies for clean hydrogen production. In the race of developing and understanding new semiconducting materials for this application, several studies have been focused on the role of oxygen vacancies, which are known to be defects with a high impact on the final optical and electrical properties of the photoelectrodes. These oxygen defective states can introduce either favorable or detrimental pathways to the overall PEC performance. The present topical review aims to summarize the role of oxygen vacancies in four of the most studied semiconducting thin film oxides (BiVO₄, Fe₂O₃, TiO₂ and WO₃) as photoanodes for solar water splitting.