Noble-metal-free metallic MoC combined with CdS for enhanced visible-light-driven photocatalytic hydrogen evolution

Abstract

Exploration of efficient and stable transition metal-based co-catalyst is of great importance for large-scale hydrogen production in the mean of photocatalytic water splitting. Herein, we propose an effective CdS/MoC photocatalyst for enhanced photocatalytic H2 evolution under visible light irradiation (≥420 nm). Upon coupling to CdS through a facile solution-mixing method, MoC was functionalized as an effective co-catalyst that accepts interface electron from CdS while promoting charges separation. Furthermore, DFT also confirmed a facilitated H* adsorption on CdS/MoC through its lowered Gibbs free energy (ΔGH*) of 0.37 eV, which is beneficial for H2 production too. As a result, the optimum photocatalyst, with 5 wt% MoC coupled to CdS, induces the best hydrogen production rate of 224.5 μmol h−1, which is 7.5 times higher than that of pristine CdS. Meanwhile, an apparent quantum efficiency (AQE) of 7.6% was also recorded at 420 nm. In terms of H2 generation, the synthesized CdS/MoC (5 wt%) is more superior to CdS/Pt (5 wt%) in an extent of 44.5%. This work confirms the competency of MoC as an effective cocatalyst and promising alternative to benchmarked Pt for photocatalytic hydrogen production from water.