Surface oxygen vacancy induced photocatalytic performance enhancement of a BiPO4 nanorod

Abstract

A high concentration of surface oxygen vacancies were successfully introduced on the BiPO_4−x nanorods via controllable hydrogen reduction. The BiPO_4−x sample with surface oxygen vacancies shows a light-gray color, although the absorption sharp edge is not changed (still about 300 nm), the absorbance enhances in the range of 300–800 nm. The enhanced level of photocatalytic performance and photocurrent are both influenced by the concentration and extent of oxygen vacancies, which can be controlled by tuning hydrogen reduction temperature and time. Only high-concentration oxygen vacancies formed on the surface layers of BiPO₄ can greatly improve the photocatalytic performance and photocurrent, while bulk oxygen vacancies will decrease the performance. The increasing of surface oxygen vacancies can results in broadening of the valence band width and narrowing of the bandgap, which can effect enhancement of the photoactivity and photocurrent, and extending the photoresponse wavelength range.