摘要： Although semiconducting gallium arsenide (GaAs) possesses an ideal band gap for efficient solar-driven fuel synthesis, it is extremely unstable in aqueous media, undergoing facile photocorrosion and therefore is seldom used. We have addressed this stability problem to some extent using a strategy of introducing a Ni-B surface catalyst onto p/n junction GaAs by in-situ photoassisted electrodeposition. A monolithic layer of Ni-B/Ga(As)Ox was generated during the Ni-B deposition process, resulting in a Ni-B/Ga(As)Ox/GaAs photoanode structure. Such structure was optimized by varying the GaAs surface architecture, electrolyte pH value and Ni-B deposition time to achieve optimal photoelectrochemical performance, together with improved stability. The optimized photoanode (Ni-B/Ga(As)Ox/shallow GaAs with 0.5 h Ni-B deposition time (~ 900 nm thickness of Ni-B/Ga(As)Ox layer) exhibited a very high photocurrent, leading to a nearly 22 hour stable photocurrent density of 20 mA/cm2, while the bare GaAs represents 60 % photocurrent loss after three hours under continuous one sun illumination (100 mW/cm2) in an alkaline media (pH=14). This remarkable performance in both photocurrent and stability directly address the current severe limitations in the application of GaAs photoanodes for solar fuel synthesis, and maybe applicable to other unstable photoelectrodes.