Triple Layered Ga2O3/Cu2O/Au Photoanodes with Enhanced Photoactivity and Stability by Iron Nickel Oxide Catalysts

In this study, the photoelectrochemical performance employing Cu2O-based photoanodes is evaluated in terms of photoactivity and stability. The electrodes are based on the p-n junction consisting of Cu2O/Ga2O3, on which an Au layer is deposited, followed by the formation of Ni-based co-catalysts. The Au layer increases the light absorption in entire wavelengths from 300 to 800 nm and leads to upward band bending at Cu2O/Au interface, thus, more photogenerated holes charges are transported to the electrolytes. The electrodeposited FeNiOx 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/cm2 at 1.23 V vs RHE with a small dark current density of 16 μA/cm2.