2H–MoSe2 nanosheet as noble-metal-free co-catalyst over Cd0·7Zn0·3S: optimizing interfacial charge transfer for enhanced photocatalytic hydrogen evolution

Developing highly efficient and low-cost noble-metal-free cocatalysts is significant for visible-light photocatalytic water splitting. Herein, 2H phase MoSe2 nanosheets were successfully synthesized via a solvent-assisted hydrothermal method and used as cocatalysts to construct heterostructure with hexagonal Cd0·7Zn0·3S nanoparticles. This well-designed heterostructure will significantly shorten the distance of charge migration to achieve efficient electron transfer between Cd0·7Zn0·3S and MoSe2. As expected, the optimized composites exhibited excellent photocatalytic hydrogen evolution (PHE) activity (3363.4 μmol g−1 in 5 h), which was 3.3 times than that of pristine Cd0·7Zn0·3S, and higher than that of 1%Pt–Cd0.7Zn0.3S. Based on electrochemical and photoluminescence results, the enhanced activity could be attributed to the lower overpotential (−0.27 V) and superior carrier separation of Cd0·7Zn0·3S/MoSe2 heterojunction. Meanwhile, 2H–MoSe2 nanosheets with large specific surface area can afford highly active Se-edge sites to absorb the protons for boosting hydrogen evolution. Moreover, Cd0·7Zn0·3S/MoSe2 photocatalysts also displayed a long-term stability without apparent debasement. This work provides new inspiration that transition metal dichalcogenides (TMDCs) as cocatalysts are promising to effectively enhance the PHE performance of sulfide solid solutions.