Enhanced visible light photocatalytic activity of sulfated CuO–Bi2O3 photocatalyst

Abstract

Sulfate (SO42−)-modified CuO–Bi2O3 composite photocatalysts with different loadings of SO42− were prepared by a facile pore impregnating method using ammonium persulfate (NH4)2S2O8 solution. The surface parameters, structure, morphology, the response ability to light, the binding energy of Bi 4f and O 1s, the hydroxyl content on the surface and the separation rate of photoinduced hole–electron pairs were characterized by Brunauer–Emmett–Teller method, X-ray diffraction, scanning electron microscopy, UV–Vis diffuse reflectance spectroscopy, X-ray photoelectron spectroscopy and surface photovoltage spectroscopy, respectively. The results reveal that sulfating of CuO–Bi2O3 decreases the band gap, increases the hydroxyl content on the surface, the separation rate of photoinduced hole-electron pairs and the adsorption of Rhodamine B on the sulfated photocatalysts. The photocatalytic activity of SO42−/CuO–Bi2O3 for decolorization of Rhodamine B aqueous solution was evaluated. The result shows that when the molar ratio of S/Bi is 5 %, SO42−/CuO–Bi2O3 exhibits the best photocatalytic activity under visible light irradiation and the possible reason is discussed.