Stable Photoelectrochemical Water Splitting Using p-n GaN Junction Decorated with Nickel Oxides as Photoanodes

Photoelectrochemical water splitting is a promising method of generating solar fuels. However, the direct solar-to-fuel approach has several critical issues on the photoelectrodes, such as bulk recombination, sluggish surface reaction kinetics, and photocorrosion. In this study, the photoanodes were prepared using a GaN p-n junction (p-n GaN) with the decoration of nickel oxide formed by the thermally annealed nickel film on the p-GaN surface layer. The surface p-n junction enhances the charge separation of the p-n GaN photoanodes, thereby increasing the photocurrent density as well as providing a higher photovoltage. The nickel oxide catalysts placed on the pn-GaN photoanodes lowered the activation energy and provided a facile route for the photogenerated holes to participate in water oxidation. As a result, the nickel oxide-decorated p-n junction GaN photoanodes exhibit a stable photocurrent density with negligible photocorrosion during the photoelectrochemical reactions.

Automated summary

The study employed nickel oxide decoration on a p-n junction GaN photoanode prepared using a thermally annealed nickel film on a p-GaN surface layer, leading to increased photocurrent density and reduced photocorrosion.