水热合成Bi_2WO_6/ZnO异质结型光催化剂及其光催化性能

Hydrothermal Synthesis and Photocatalytic Performance of Bi_2WO_6/ZnO Heterojunction Photocatalysts

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 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.