In Situ Synthesized Rodlike MoS₂ as a Cocatalyst for Enhanced Photocatalytic Hydrogen Evolution by Graphitic Carbon Nitride without a Noble Metal

Dependence on a noble metal cocatalyst is one of the main obstacles to the practical application of graphitic carbon nitride (g-CN) for photocatalytic hydrogen evolution. In this paper, a noble-metal-free photocatalyst, g-CN/MoS2 composite, was in situ synthesized via a gas–solid reaction where rodlike MoO3 was sulfurized to form MoS2 by the byproduct generated during the thermal condensation of thiourea, the precursor of g-CN. The composite exhibited an enhanced photocatalytic activity under irradiation of visible light, whose hydrogen evolution rate increased from 0.99 to 13.31 μmol·h–1, 13.44 times higher than that of pristine g-CN. On the basis of a series of characterization results, the formation and photocatalysis mechanism of g-CN/MoS2 was proposed, and the enhancement was attributed to the introduction of rodlike MoS2, which played the role as the cocatalyst instead of a noble metal to reduce the hydrogen evolution overpotential. This work provides a convenient method to synthesize a transition metal sulfide based on graphitic carbon nitride.