Enhancing the charge transfer and photoelectrochemical performance of the BiVO 4 /WO 3 heterojunction via gradient surface/interface Co–Mo doping

We prepared a CoBiVO 4 Mo/WO 3 photoanode by selectively introducing Mo at the interface and doping Co on the surface of the heterojunction. This enabled precise control over the spatially graded distribution of the two dopants, boosting charge transfer and photoelectrochemical performance.