Solvent effect on morphological evolution and photocatalytic property of α-SnWO4

Abstract Alpha-phase stannous tungstate (α-SnWO 4 ) nano-crystals with different morphologies were successfully synthesized by changing water content in ethylene glycol (EG) using a solvothermal method. The obtained samples were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). It was found that the morphologies of α-SnWO 4 samples transformed from nanostrip to nanosheet with increasing water content, which is ascribed to the improved mass transfer in the water medium. Photocatalytic activities of the products were evaluated by the degradation of methyl orange (MO) under visible light irradiation. The microstructure of α-SnWO 4 played an important role on its photocatalytic activity. As a result, the α-SnWO 4 with high crystallinity and large surface area exhibited the best photocatalytic activity and its degradation efficiency reached to 90.4% within 30 min. Based on active species trapping experiments, both hole (h + ) and superoxide radical (·O 2 − ) are dominant active species in the photodegradation of MO over α-SnWO 4 nano-materials and thus a possible mechanism was proposed.