Titanium carbide MXenes coupled with cadmium sulfide nanosheets as two-dimensional/two-dimensional heterostructures for photocatalytic hydrogen production

Two-dimensional (2D)/2D heterostructures with close contact are believed to be important for photocatalysis owing to a 2D ultrathin structure, a large surface area, and an efficient carrier separation or transfer. In this study, we designed and prepared a unique 2D/2D cadmium sulfide (CdS) nanosheet (NS)@titanium carbide (Ti3C2) MXene composite photocatalyst. The results show that the CdS NSs can be controllably assembled on conductive Ti3C2 MXene via a one-step hydrothermal strategy. The 2D/2D CdS NS@Ti3C2 MXene composites with 5 mg of Ti3C2 MXene show a higher photocatalytic performance (1.73 mmol h-1 g-1) than pure CdS NSs (0.37 mmol h-1 g-1) and CdS NS@Ti3C2 MXene composites with other MXene contents (3 mg, 7 mg, 10 mg, and 20 mg). The improved photocatalytic activity can be attributed to the high surface area as confirmed by a BET analysis and enhanced charge separation activity between CdS and Ti3C2 MXene.