Insight into the Kinetic Influence of Oxygen Vacancies on the WO₃ Photoanodes for Solar Water Oxidation

Abstract

Improvements to solar water oxidation performance for WO₃ photoanodes due to oxygen vacancies have in general been ascribed to thermodynamic effects. Detailed insights into the water oxidation kinetics for WO₃ photoanodes with oxygen vacancies are still lacking. Here, our experimental and computational investigations revealed that the water oxidation pathway on WO₃ photoanodes with oxygen vacancies is more inclined to follow the four-hole pathway. This finding reasonably explained the common observations of higher faradaic efficiency for oxygen evolution, better stability, and faster kinetics for water oxidation usually achieved on the WO₃ photoanodes with oxygen vacancies.