Determining the role of oxygen vacancies in the photoelectrocatalytic performance of WO 3 for water oxidation

performances. Our conclusion, that an optimal - neither too high nor too low - concentration of oxygen vacancies is required for optimum photoelectrochemical performance, is discussed in terms of the competing beneficial and detrimental impact these defects have on charge separation and transport, as well as the implications held for other highly doped materials for photoelectrochemical water oxidation.