Highly efficient hydrogen generation in water using 1D CdS nanorods integrated with 2D SnS2 nanosheets under solar light irradiation

Abstract

The development of low-cost and noble-metal-free catalysts for the photoconversion of water into hydrogen (H-2) is of great interest. Here, 2D tin(IV) sulfide (SnS2) ultrathin nanosheets as co-catalysts are coupled with 1D cadmium sulfide (CdS) nanorods for the photosplitting of water into H-2. The design of the catalyst can facilitate the passivation of the physiochemical properties of CdS and enhance H-2 evolution activity. The prepared CdS/SnS2 composite catalyst increases the H-2 generation activity and exhibits excellent and continuous long-term photostability. The H-2 evolution rate of the optimized CdS/SnS2 composite is approximately 9-fold that of pristine CdS nanorods. The characterization results of the CdS/SnS2 composite reveal that the loading of SnS2 can enhance the synergistic effects of the photocatalyst due to the effective separation, large number of exposed catalytic sites, and highly dispersed nature of the layered SnS2. Several characterization outcomes of CdS/SnS2 are examined in detail (e.g., structural and surface elemental results of transmission electron microscopy, X-ray diffraction analysis, X-ray photoelectron spectroscopy). Further, the optoelectrical properties and charge-carrier excitations are investigated via ultraviolet diffuse reflectance spectroscopy, photoluminescence spectroscopy, and photoelectrochemical analysis. The proposed CdS/SnS2 composite is a promising low-cost, noble-metal-free, and high-efficiency catalyst for the photocatalytic water-reduction reaction.