Highly efficient photoanode in visible light water splitting through development of Z-scheme structure between compositing TiO2 with GQDs and Ba doped VO2 (m) with smart selection of Ag nanoparticles sites

Abstract

A highly efficient photoanode for water splitting under visible light is designed by placing Ag nanoparticles (NPs) at the interface of Ba doped VO2 (m) (BaV) and compositing hierarchical porous TiO2 NPs with a graphene quantum dots layer (TG). In fact, the electron flow direction in the photoanode is simply adjusted to develop the Z-scheme structure through solution processing assembly. A very high photocurrent of 2.15 mA cm−2 at 1.23 V vs. RHE is achieved for sequentially assembled reduced graphene oxide (RGO)/BaV/Ag/Ag@TG photoanode. This value is 30 times higher than that of pristine TiO2 photoanode (0.07 mA cm−2 at 1.23 V vs. RHE) and a 70 % increase over type-II heterojunction with RGO/Ag@TG/BaV assembly. Importantly, the stability of this Z-scheme photoanode is 10 times higher than its type-II heterojunction counterpart, making it a promising option for practical applications in water splitting under visible light.