Stable and Efficient Photoelectrochemical Water Splitting of GaN Nanowire Photoanode Coated with Au Nanoparticles by Hot-Electron-Assisted Transport

Photoelectrochemical (PEC) water splitting is a promising approach for the conversion of solar energy into chemical fuels. Increasing the surface area and decorating the semiconductors with noble metal nanoparticles (NPs) is an optimistic approach to improve the PEC water splitting efficiency. Herein, we report the fabrication of an efficient and reliable photoanode by depositing Au nanoparticles (NPs) on GaN nanowires (NWs). The Au NPs/GaN NW photoanode exhibited 55% improvement in the photocurrent density compared to that of bare GaN NWs. The enhanced performance is attributed to the increased incident photon-to-current conversion efficiency of 34% in the ultraviolet region and 14.5% in the visible region. The stability of Au NPs/GaN NW photoanode was also notably improved. These significant improvements in the efficiency of the Au NPs/GaN NW photoanodes are associated with efficient charge generation and transportation due to light harvesting and trapping of hot electrons by Au NPs at the GaN NW photoelectrode.