In Situ Formation of WO3-Based Heterojunction Photoanodes with Abundant Oxygen Vacancies via a Novel Microbattery Method

Non-stoichiometric ratio semiconductor materials have exhibited excellent performance in energy conversion and storage fields. However, the hydrogen treatment method that is commonly used to introduce oxygen vacancies is expensive and dangerous. In this paper, a novel microbattery method using Zn powder and Fe powder as reductant has been developed to synthesize the oxygen vacancy modified WO3-x films and oxygen-deficient heterojunction films (ZnWO4-x/WO3-x and Fe2O3-x/WO3-x) at room temperature. The as-prepared WO3-x and ZnWO4-x/WO3-x heterojunction films exhibit improved photoelectrochemical performance. It is worth noting that this microbattery method can quickly introduce oxygen vacancies into semiconductor materials, including powders and films at room temperature.