在不同温度下(120~220℃), 利用水热法制备了含1wt%、2wt%、4wt% 和8wt% Bi2WO6的异质结型Bi2WO6/ZnO复合光催化剂, 采用X射线粉末衍射(XRD)、扫描电镜(SEM)、傅里叶变换红外光谱(FT-IR)、紫外可见漫反射(UV-Vis) 吸收光谱及光致发光光谱(PL)等系列手段对所制备的光催化剂进行了表征, 并以紫外光(365nm)为光源, 酸性橙II为降解对象, 进行光催化活性测试, 考察了不同Bi2WO6复合量及不同水热温度对ZnO光催化剂反应活性的影响.研究表明, 异质结型Bi2WO6/ZnO复合光催化剂的光催化活性明显优于纯ZnO和Bi2WO6. 当复合4wt%Bi2WO6水热处理温度为150℃时, 所制备的复合光催化剂的光催化活性最佳, 为纯ZnO的2.6倍.活性提高的主要原因是形成的Bi2WO6/ZnO异质结能显著降低光生电子和空穴对的复合几率, 并改善了异质结型Bi2WO6/ZnO复合光催化剂的表面性能.
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 catalysts 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 formation 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.
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