WO3/Cu2O heterojunction for the efficient photoelectrochemical property without external bias

Photoelectrochemical (PEC) splitting of water to produce hydrogen without external bias is an important approach to resolve the serious energy crisis. Herein, we prepared a PEC cell system based on the WO3/Cu2O heterojunction in situ grown on the FTO glass substrates by a seed-mediated hydrothermal followed by electrodeposition method. Under visible light illumination, the pure WO3 exhibited no photocurrent at 0 V vs. RHR in aqueous Na2SO4 and the pure Cu2O struggled with serious photo-corrosion. By contrast, the obtained Z-scheme WO3/Cu2O-30 min heterojunction can not only effectively suppress the corrosion of Cu2O but also obtained a photocurrent density of 12 μA cm−2 without external bias or adding sacrificial agent. Additionally, the possible mechanism of a Z-scheme system was also proposed based on the XPS analysis and the experimental results. Thus, this study reveals that the as-obtained Z-scheme WO3/Cu2O-30 min heterojunction has a great prospect in the PEC cell system without external bias.