An amorphous MoS modified g-CN composite for efficient photocatalytic hydrogen evolution under visible light.

In this work, an MoS /g-CN composite photocatalyst was successfully fabricated by a sonochemical approach, where amorphous MoS was synthesized using a hydrothermal method with NaMoO·HO, HSiO(WO) and CHCSNH as precursors, and g-CN nanosheets were produced using a two-step thermal polycondensation method. The hydrogen-evolution performance of the MoS /g-CN composite was tested under visible light. The results show that the H-evolution rate of the MoS /g-CN (7 wt%) photocatalyst reaches a maximum value of 1586 μmol g h, which is about 70 times that of pure g-CN nanosheets. The main reason is that amorphous MoS forms intimate heterojunctions with g-CN nanosheets, and the introduction of MoS into g-CN nanosheets not only enhances the ability to convert H into H, but also promotes the separation of photoinduced electron-hole pairs for the photocatalyst. BET analysis shows that the specific surface area and pore volume of g-CN are decreased in the presence of MoS . XPS analysis manifests that MoS provides a number of active sites. Mott-Schottky plots show that the conduction band of MoS (-0.18 V , pH = 7) is more negative than that of g-CN nanosheets.