Template-Free Synthesis of Nanostructured CdxZn1-xS with Tunable Band Structure for H2 Production and Organic Dye Degradation Using Solar Light

We have demonstrated a template-free large-scale synthesis of nanostructured CdxZn1-xS by a simple and a low-temperature solid-state method. Cadmium oxide, zinc oxide, and thiourea in various concentration ratios are homogenized at moderate temperature to obtain nanostructured CdxZn1-xS. We have also demonstrated that phase purity of the sample can be controlled with a simple adjustment of the amount of Zn content and nanocrystalline CdxZn1-xS (x = 0.5 and 0.9) of the hexagonal phase with 6-8 nm sized and 4-5 nm sized Cd0.1Zn0.9S of cubic phase can be easily obtained using this simple approach. UV-vis and PL spectrum indicate that the optical properties of as synthesized nanostructures can also be modulated by tuning their compositions. Considering the band gap of the nanostructured CdxZn1-xS well within the visible region, the photocatalytic activity for H-2 generation using H2S and methylene blue dye degradation is performed under visible-light irradiation. The maximum H-2 evolution of 8320 mu mol h(-1)g(-1) is obtained using nanostructured Cd0.1Zn0.9S, which is four times higher than that of bulk CdS (2020 mu mol h(-1) g(-1)) and the reported nanostructured CdS (5890 mu mol h(-1)g(-1)). As synthesized Cd0.9Zn0.1S shows 2-fold enhancement in degradation of methylene blue as compared to the bulk CdS. It is noteworthy that the synthesis method adapted provides an easy, inexpensive, and pollution-free way to synthesize very tiny nanoparticles of CdxZn1-xS with a tunnable band structure on a large scale, which is quite difficult to obtain by other methods. More significantly, environmental benign enhanced H-2 production from hazardous H2S using CdxZn1-xS is demonstrated for the first time.