Facile construction of MoS2 decorated CdS hybrid heterojunction with enhanced hydrogen generation performance

Abstract

Promoting the charge separation to improve photocatalytic performance of semiconductor photocatalysts is very important in the field of artificial photosynthesis. Here, a novel MoS2/CdS 2D–2D ultrathin nanosheet heterostructure was fabricated via a one-pot solvothermal route. The obtained 2D–2D MoS2/CdS nanojunction has not only provided large contact areas, but also shortened the charge transport distance, resulting in significantly enhanced photocatalytic H2 evolution property. The composites that were synthesized were examined using X-ray diffraction (XRD), Field emission scanning electron microscope (FESEM), Transmission electron microscope (TEM), UV-vis diffuse reflectance spectra (DRS), Photoluminescence (PL) and X-ray photoelectron spectra (XPS) analysis. By optimizing the 2D MoS2 amounts in the heterojunction, the 5 wt.% 2D/2D MoS2/CdS heterojunction displayed the maximal photocatalytic H2 evolution rate of 4449 μmolh−1g−1 under visible light irradiation in the presence of lactic acid as the sacrificial reagent, which was 6 times higher than that of pristine 2D CdS. Based on the photoelectrochemical and photoluminescence spectra tests, it could be deduced that the charge separation and transfer of 2D/2D MoS2/CdS heterojunction was tremendously improved, and the recombination of photoinduced electron-hole pairs was effectively impeded. Moreover, the 2D MoS2 was used as a cocatalyst to provide the abundant active sites and lower the overpotential for H2 generation reaction. The current work would offer an insight to fabricate the 2D/2D heterojunction photocatalysts for splitting H2O into H2.