Constructing a noble-metal-free 0D/2D CdS/SnS₂heterojunction for efficient visible-light-driven photocatalytic...

Semiconductor photocatalysis has attracted the attention of a wide audience for its outstanding capabilities in water purification and energy conversion. Herein, a noble-metal-free nanoheterojunction is created by planting zero-dimensional (0D) CdS nanograins, of 10-20 nm in size, on the surface of 2D SnS₂nanosheets (NSs) using anin situchemical bathing deposition process, where SnS₂NSs have an average diameter of 400 nm and thicknesses of less than 20 nm. The possible formation mechanism of the CdS/SnS₂(CS/SS) heterogeneous nanostructure is elaborated upon. The catalytic activities over CS/SS nanocomposites for the photodegradation of organic dye and hydrogen evolution from photolysis water splitting are examined under visible light irradiation. The apparent rate constant (k) of the optimal CS/SS-3 composite in the decontamination of methylene blue (MB) is up to 3.34 and 1.87 times as high as that of pristine SnS₂and pure CdS counterparts, respectively. The optimized CS/SS-3 sample consistently achieves the highest photocatalytic hydrogen production rate, at 10.3 and 5.7 folds higher than that of solo SnS₂and CdS panels, respectively. The boosted photocatalytic capacities of CdS/SnS₂heterostructures are essentially attributed to the formation of the closely interfacial incorporation of CdS and SnS₂semiconductors, resulting in the effective charge transportation and spatial separation of the photoinduced electron-hole pairs. Furthermore, the traditional type-II charge transfer pathway is proposed based on the perfect band structure and the free radical experiment results.