Direct Photoinduced Synthesis of Amorphous CoMoSx Cocatalyst and Its Improved Photocatalytic H2-Evolution Activity of CdS

Compared with the well-known Pt cocatalyst, molybdenum sulfide is one of the most prospective alternatives for developing highly efficient photocatalytic H2-evoultion materials. To further improve its H2-evoultion activity, it is highly required to further optimize the electronic and surface structures of molybdenum sulfide cocatalyst. Herein, a novel amorphous molybdenum-based bimetallic sulfide (a-CoMoSx) was prepared and loaded on the CdS surface by a photoinduced electron-reduction method to promote the interfacial H2-production rate of CdS. It is found that loading a-CoMoSx cocatalyst can markedly enhance the H2-generation activity of CdS photocatalyst, which is significantly higher than that of pure CdS and a-MoS2/CdS by a factor of 26.3 and 3.1 times. More importantly, in addition to CdS, the a-CoMoSx can also serve as the general electron cocatalyst to obviously promote the H2-production activity of well-known TiO2 (typical UV-responsive titanium dioxide) and g-C3N4 (novel visible light-responsive organic semiconductors). According to the present results, an electron-cocatalyst mechanism of a-CoMoSx is proposed to explain the enhanced photocatalytic H2-production performance, namely, amorphous CoMoSx can rapidly capture electrons and then quickly transfer the electrons to the active sites (its unsaturated S atoms and defect sites) to effectively enhance the interfacial H2-production reaction. In consideration of its facile synthesis, low cost, and superior performance, the amorphous CoMoSx appears to be one of the most prospective cocatalysts for photocatalytic water splitting.