Construction of Z-type In2O3@InP heterostructure with enhanced photo-assisted electrocatalytic water splitting for hydrogen production

We report an in-situ construction strategy of Z-type In2O3@InP hydrogen evolution reaction (HER) electrocatalyst with well-defined core-shell structure on nickel foam (In2O3@InP/NF) via sequential hydrothermal, annealing, and phosphating steps. The phosphating time dramatically affects the morphology, crystal phase, elemental composition, and optical properties of In2O3@InP. The resulting electrode obtained with 2 h of phosphating time has smaller overpotentials and Tafel slope, larger TOF and ECSA, and lower charge transfer resistance compared to In2O3/NF. The better activity reveals the promoted roles of InP that can provide more active sites, facilitate charge transfer, and accelerate the adsorption of H* species. The photo-assisted electrocatalytic activity for HER is significantly enhanced attributed to the strong light absorption capacity of InP, superior energy level configuration of In2O3 and InP, and excellent transient light response of In2O3@InP. Furthermore, the electrode has favorable stability and durability, and the morphology and surface chemical state have no essential changes after the photo-assisted HER stability test.