GaP/GaPN core/shell nanowire array on silicon for enhanced photoelectrochemical hydrogen production

Abstract Simultaneously improving the efficiency and stability on a large scale is significant for the development of photoelectrochemical (PEC) water splitting systems. Here, we demonstrated a novel design of GaP/GaPN core/shell nanowire (NW) decorated p-Si photocathode for improved PEC hydrogen production performance compared to that of bare p-Si photocathode. The formation of the p-n junction between p-Si and GaP NW promotes charge separation, and the lower conduction band position of GaPN relative to that of GaP further facilitates the transfer of photogenerated electrons to the electrode surface. In addition, the NW morphology both shortens the carrier collection distance and increases the specific surface area, which result in superior reaction kinetics. Moreover, introduction of N in GaP is beneficial for enhancing the light absorption as well as stability. Our efficient and facile strategy can be applied to other solar energy conversion systems as well.