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

Porous ZnO/SnS2 nanocomposites with adjustable SnS2 contents were prepared viamicrowave-assisted heating of different aqueous solutions of SnS2 precursors in the presenceof fixed amount of ZnCO3 nanoparticles at pH 7. The structures, compositions, BETspecific surface areas, and optical properties of the as-prepared products were characterizedby X-ray diffraction, energy dispersive X-ray spectroscopy, transmission electron microscopy,N2 adsorption, and UV-Vis absorption spectra. Photocatalytic activities of thesamples were tested by the removal of aqueous ciprofloxacin, C r VI , and methylene blueunder visible-light ( λ > 420 nm) irradiation. The experimental results reveal that the as-preparedheterogeneous nanostructures exhibit much higher visible-light-driven photocatalyticactivity for the degradation of the pollutants than pure SnS2 nanocrystals. The photocatalyticdegradation rates C t / C 0 of the pollutants for the most active heterogeneousnanostructure are about 10, 49, and 9 times higher than that of pure SnS2. The enhancedphotocatalytic activities exhibited by the heterojunctions could be ascribed to the synergeticeffect of enhanced absorption in the visible region and the reduced rate of charge carrier recombinationbecause of efficient separation and electron transfer from the SnS2 to ZnOnanoparticles.