水热反应条件对多孔球状Bi2WO6光催化剂结构及性能的影响

采用水热法制备了Bi₂WO₆光催化剂, 考察了水热反应温度、 水热反应时间及前驱体溶液pH值等条件对其对乙烯可见光催化活性的影响, 并通过X射线衍射(XRD)、 扫描电子显微镜(SEM)、 紫外-可见漫反射光谱(UV-Vis DRS)和比表面积分析等对催化剂的晶相组成、 微观形貌和光学性质等进行表征. 结果表明, 在水热反应温度为120 ℃、 水热反应时间为12 h、 前驱体溶液pH=0.5条件下, Bi₂WO₆光催化剂经过各向异性生长以及自组装奥斯特瓦尔德成熟(Ostwald ripening)过程, 形成由二维纳米薄片自组装的多孔微球状结构, 有效增大了与乙烯气体的接触面积, 禁带宽度降至2.86 eV, 可见光响应范围拓宽, 表现出优异的光催化性能, 在可见光下240 min内对乙烯的降解率达到13.69%.

Effects of Hydrothermal Reaction Conditions on the Structure and Properties of Porous Spherical Bi2WO6 Photocatalyst †

Bi₂WO₆ photocatalysts were prepared via hydrothermal method. The effects of hydrothermal reaction temperature, hydrothermal time and pH value of precursor solution on the catalytic activity of the catalysts for ethylene degradation under visible-light irradiation were investigated. The crystal composition, micro-morphology and optical properties were characterized by X-ray powder diffraction(XRD), scanning electron microscopy(SEM), UV-Visible diffuse reflectance spectroscopy(UV-Vis DRS) and BET surface area analysis. The results show that at the conditions of 120 ℃, 12 h, pH=0.5, the Bi₂WO₆ photocatalyst undergoes anisotropic growth and Ostwald ripening process to form a porous microsphere structure self-assembled by two-dimensional nanosheets, which effectively increases the contact area with ethylene gas. The band gap width of the catalyst is reduced to 2.86 eV, and the visible light response range is widened. The degradation rate of ethylene reached 13.69% with in 240 min under visible light irradiation.