Engineering oxygen vacancies by one-step growth of distributed homojunctions to enhance charge separation for efficient photoelectrochemical water splitting

Abstract

How to limit the recombination of photogenerated carriers is one of the grand challenges for exploring efficient photoelectrochemical (PEC) cells. In the present work, an engineering of oxygen vacancies within photoanodes by constructing distributed homojunctions for enhanced PEC performance is proposed. The distributed homojunctions are attributed to the formed hierarchical layers within the photoanodes, which were accomplished by one-step aqua-regia hydrothermal strategy. It is evidenced that the distributed homojunctions produced an improved spatial distribution of built-in electric field, thus significantly facilitating the charge separation for the PEC cells. As a proof of concept, the assembled WO3 photoanode exhibits a photocurrent density up to 1.81 mA cm−2 at 1.23 V vs. RHE in neutral electrolyte solution under AM 1.5G illumination without any cocatalysts and dopants, which is the state-of-the-art one ever reported.