制备方法对Bi_2WO_6光催化剂结构及可见光催化降解乙烯性能的影响

Effects of Preparation Methods on Bi_2WO_6 Structure and their Performance in Visible-Light Driven Photocatalytic Degradation of Ethylene

通过高温固相法、微乳液法、水热法、醇水混合溶剂热法、和乙二醇溶剂热法制备出Bi_2WO_6光催化剂。采用X射线衍射(XRD)、场发射扫描电镜(SEM)、紫外-可见吸收光谱(UV-Vis)对样品的晶体结构、微观形貌、吸光性能进行表征,并考察其在可见光下降解乙烯的光催化性能。结果表明:制备方法对Bi_2WO_6光催化剂的微观结构和光催化性能都有明显的影响,其中高温固相法所得样品的颗粒粒径最大且易团聚,光催化活性最低,对乙烯的降解率仅为5.85%。乙二醇溶剂热法制备的Bi_2WO_6样品的平均粒径约为100~200 nm,禁带宽度为2.90 eV,对乙烯的降解率最高,为13.82%,比高温固相法提高了136.24%。

Bi2WO6 catalysts were prepared by solid-phase method,microemulsion method,hydrothermal method,ethanol-water mixed solvothermal method and ethylene glycol solvothermal method,respectively.Crystal structure,microstructure and light absorption performance were characterized by X-ray diffraction(XRD),field emission scanning electron microscopy(FE-SEM)and ultraviolet-visible diffuse reflectance spectroscopy(UV-Vis).Photocatalytic activity of the catalysts was evaluated by ethylene degradation under visible-light irradiation.The results show that different preparation methods have obvious effects on the microstructure and photocatalytic performance of the Bi2WO6 photocatalysts.Samples prepared by the solid-phase method have the maximum particle size with easy agglomeration,which presents the poorest photocatalytic activity(5.85%).The average particle size of the sample prepared by the ethylene glycol solvothermal method is about 100~200 nm,and the band gap is 2.90eV.Its photocatalytic activity is 13.82%,which shows the highest ethylene degradation rate among the five methods.The degradation rate is 136.24%higher than that of the solid-phase method.