Microwave-Assisted Synthesis of Porous ZnO/SnS2 Heterojunction and Its Enhanced Photoactivity for Water Purification

Abstract

Porous ZnO/SnS2 nanocomposites with adjustable SnS2 contents were prepared via microwave-assisted heating of different aqueous solutions of SnS2 precursors in the presence of fixed amount of ZnCO3 nanoparticles at pH 7. The structures, compositions, BET specific surface areas, and optical properties of the as-prepared products were characterized by X-ray diffraction, energy dispersive X-ray spectroscopy, transmission electron microscopy, N2 adsorption, and UV-Vis absorption spectra. Photocatalytic activities of the samples were tested by the removal of aqueous ciprofloxacin, CrVI, and methylene blue under visible-light (> 420 nm) irradiation. The experimental results reveal that the as-prepared heterogeneous nanostructures exhibit much higher visible-light-driven photocatalytic activity for the degradation of the pollutants than pure SnS2 nanocrystals. The photocatalytic degradation rates Ct/C0 of the pollutants for the most active heterogeneous nanostructure are about 10, 49, and 9 times higher than that of pure SnS2. The enhanced photocatalytic activities exhibited by the heterojunctions could be ascribed to the synergetic effect of enhanced absorption in the visible region and the reduced rate of charge carrier recombination because of efficient separation and electron transfer from the SnS2 to ZnO nanoparticles.