Highly efficient visible"light"driven photocatalytic hydrogen production using robust noble"metal"free Zn0.5Cd0.5S@graphene composites decorated with MoS2 nanosheets

Solar water splitting using semiconductor photocatalysts is considered to be one of the economical and significant techniques for hydrogen evolution. In this study, graphene–Zn_xCd_1−xS (ZCS) heterojunction is fabricated by hydrothermal method followed by simple photodeposition of ultrathin few layers of molybdenum sulfide (MoS₂) nanosheets. The results show that compared with pristine ZCS and 1 wt% graphene mixed ZCS photocatalysts, the 1 wt% graphene and 1 wt% MoS₂ photodeposited ZCS composited sample shows 39.5 mmol h⁻¹ g⁻¹ hydrogen production activity, which is 6.9 and 1.9 times significantly higher, respectively, with an apparent quantum yield of 53% at 420 nm visible light is recorded. The improved photocatalytic activity can be attributed to the formation of heterostructure interface between p-type MoS₂ nanosheets with n-type ZCS host, which allows for the faster transfer of the photogenerated electrons and thus significantly promotes the separation of photogenerated charge carriers.