Ni2P–Ni2P4O12 enhanced CdS nanowires for efficient visible light photocatalytic hydrogen production

Abstract

Intrinsic charge carrier recombination, narrow visible light absorption and poor durability restrain the photoactivity for solar-to-H2 production. Here, noble-metal-free binary co-catalyst Ni2P–Ni2P4O12 was synthesized by a simple one-step thermal phosphorylation method for enhancing CdS nanowires in visible-light-driven hydrogen generation, where the CdS nanowires are uniformly dispersed on the surface of Ni2P–Ni2P4O12 through in-situ solvothermal strategy. The photocatalytic hydrogen production rate of 5 ​wt% Ni2P–Ni2P4O12/CdS nanowires can reach 5093 ​μmol ​g−1 ​h−1 using Na2S–Na2SO3 as sacrificial agent under the irradiation of visible light (λ ​> ​420 ​nm), which is about 16 times for CdS nanowires (316 ​μmol ​g−1 ​h−1). In the cycling experiments, the composite catalyst shows good stability and the hydrogen production rate remains about 83% of the initial value. The interface structure construction between CdS nanowires and Ni2P–Ni2P4O12 result in the excellent photocatalytic activity, broaded visible light absorption and stability. Specifically, Ni2P–Ni2P4O12 can effectively promote the separation of electron hole pairs in space, in which Ni2P4O12 can accept H+ ions and Ni2P can reduce the over potential of H+ reduction, resulting in the synergically promotion in the photocatalytic activity. The cost-effective ternary photocatalyst exhibits great potential for sustainable and high-efficiency photocatalytic water splitting, and Ni2P–Ni2P4O12 may be suitable to modify a wider variety of semiconductor photocatalysts.