Hydrothermal Synthesis and Photocatalytic Performance of Bi_2WO_6/ZnO Heterojunction Photocatalysts

A series of Bi2WO6/ZnO heterojunction photocatalysts with different Bi2WO6 concentrations(1wt%,2wt%,4wt%,8wt%) were prepared by hydrothermal method at different temperatures(120℃?220℃).The prepared pure ZnO,Bi2WO6 and Bi2WO6/ZnO heterojunction photocatalysts were characterized by X-ray diffraction(XRD),scanning electron microscope(SEM),Fourier transform infrared spectroscope(FT-IR),UV-Vis diffuse reflectance spectra,and photoluminescence(PL) spectroscope,respectively.The photocatalytic activity of the prepared cata-lysts was evaluated by photocatalytic degradation of acid orange II under UV light(λ=365nm) irradiation.Results show that the photocatalytic activity of Bi2WO6/ZnO heterojunction photocatalysts is superior to that of pure ZnO and Bi2WO6.The optimal concentration of Bi2WO6 is 4wt% and the best hydrothermal temperature is 150℃.Under the above conditions,the prepared composite catalyst shows about 2.4 times in activity of the pure ZnO.The for-mation of Bi2WO6/ZnO heterojunction could effectively suppress the recombination of the photo generated electron and hole pairs and result in an increase in photocatalytic activity.Moreover,more surface OH groups over the Bi2WO6/ZnO heterojunction photocatalysts will further benefit the improvement of photocatalytic activity.