Hierarchical charge transfer pathways in MoC/MoS2 cocatalysts for enhanced CdS photocatalytic hydrogen evolution

Efficient photocatalytic hydrogen evolution is often hindered by sluggish charge transfer within the catalyst and slow interfacial reaction kinetics. Herein, we construct a highly active and durable ternary MoC/MoS 2 /CdS (MMS) photocatalyst by precisely tailoring the MoC/MoS 2 cocatalyst composition and architecture through in-situ vulcanization. The optimized MMS composite delivers a remarkable hydrogen evolution rate of 38.3 mmol g −1  h −1 under simulated solar irradiation, outperforming MoC/CdS and MoS 2 /CdS by factors of 3.4 and 1.8, respectively. Mechanistic studies reveal that MoC acts as an efficient electron reservoir and, together with MoS 2 , constructs a hierarchical charge transfer network, boosting photogenerated electron separation efficiency by 2.7-fold. Moreover, the conductive MoC framework synergizes with the edge active sites of MoS 2 , significantly reducing the overpotential for hydrogen evolution. Density functional theory calculations further demonstrate that the strong interfacial electronic coupling between MoC(110) and MoS 2 (002) facets induces charge redistribution, yielding a low-barrier transfer pathway and optimizing the hydrogen adsorption free energy (ΔG H*  = −0.12 eV). This work provides new mechanistic insights and a design strategy for developing high-performance metal sulfide–based synergistic cocatalyst systems.