Vacancy-doped homojunction structural TiO₂ nanorod photoelectrodes with greatly enhanced photoelectrochemical activity

In this study, we report a simple, effective and universal approach to fabricate homojunction structural TiO₂ nanorod array photoelectrodes through doping of gradient distributed oxygen vacancies introduced by annealing in high vacuum with controlled time. The homogeneous junction structure promotes the separation and transport of photoexcited charge carriers, and the photocurrent density of TiO₂ nanorod arrays annealed in high vacuum for 2 h was 20 times higher than that of the pristine TiO₂ nanorod arrays. The results indicate that annealing in high vacuum with controlled time could form a homojunction structure, which is an effective approach for further enhancing the performance of UV–visible light driven photocatalytic materials for water splitting.