LAUSR

Photoelectrochemical (PEC) water splitting is a promising clean route to hydrogen fuel. The best performing materials (III/V semiconductors) require surface passivation, as they are liable to corrosion, and a surface co-catalyst to facilitate water splitting. At present, optimal design photoelectrodes combining with oxygen evolution catalyst remains a significant materials challenge. Here, we demonstrate that nickel-coated amorphous three-dimensional (3D) TiO 2 core-shell nanorods on a TiO 2 thin film function as an efficient hole-extraction layer and serve as a protection layer for the GaAs photoanode. Transient-absorption spectroscopy (TAS) demonstrated the role of nickel-coated (3D) TiO 2 core-shell nanorods in prolonging photogenerated charge in GaAs, resulting in a higher catalytic activity. This strategy may open the potential of utilizing this low-cost (3D) nanostructured catalyst for decorating narrow band gap semiconductor photoanodes for PEC water splitting devices.