Triple layered Ga2O3/Cu2O/Au photoanodes with enhanced photoactivity and stability prepared using iron nickel oxide catalysts

Abstract

In this study, the photoelectrochemical performance of Cu₂O-based photoanodes is evaluated in terms of photoactivity and stability. The electrodes are based on the p–n junction consisting of Cu₂O/Ga₂O_3, on which an Au layer is deposited, followed by the formation of Ni-based co-catalysts. The Au layer increases the light absorption in the entire wavelength range from 300 to 800 nm and leads to upward band bending at the Cu₂O/Au interface; thus, more photogenerated hole charges are transported to the electrolytes. The electrodeposited FeNiO_x thin layer significantly decreases the overpotential and increases the photoactivity; thus, the photoelectrochemical cell consisting of the Cu₂O-based photoanode and platinum yields a photocurrent density of about 5.15 mA cm⁻² at 1.23 V vs. RHE with a small dark current density of 16 μA cm⁻².