Multicomponent transition metal phosphides derived from layered double hydroxide double-shelled nanocages as an efficient non-precious cocatalyst for hydrogen production

Abstract

Non-precious transition metal phosphides (TMPs) are emerging as the most promising substitutes for expensive noble metal-based co-catalysts for the hydrogen evolution reaction. While the synthesis of TMPs is well established, it is extremely challenging to design porous multicomponent transition metal phosphides (MCTMPs) to overcome the drawbacks of TMPs, namely, limited active sites and low surface area. Herein, we synthesized MCTMPs (containing Co, Ni, and Mo) from layered double hydroxide double-shelled nanocages by a metal-organic framework (MOF) template-engaged strategy. Benefiting from the rich structural features, high specific surface area, and multiple active components in the composition, the MCTMPs manifest greatly enhanced photocatalytic hydrogen evolution properties when integrated with CdS semiconductor nanorods. The observed hydrogen evolution rate is 53.76 fold higher than that of the bare CdS nanostructures and 4.37 times higher than that of the benchmark 2 wt% Pt-CdS nanorods, with a quantum efficiency of 40.6%. A possible explanation for the enhancement of the photocatalytic activity was proposed on the basis of the separation efficiency of the photogenerated charge carriers; this was further confirmed by photocurrent, electrochemical impedance spectroscopy, and photoluminescence studies. We believe that the work presented here represents a novel design strategy for MCTMPs with active noble metal free components with applications as sunlight-driven photocatalysts for hydrogen production through water splitting.