CuO负载空心球状BiVO_4可见光矿化气相甲苯

Photocatalytic Degradation of Gas-Phase Toluene over CuO Loaded BiVO_4 Hollow Nanospheres under Visible-Light Irradiation

以碳球为模板,采用溶胶-凝胶法制备空心球状BiVO4,浸渍法制备CuO负载BiVO4.运用X射线衍射(XRD)、扫描电镜(SEM)、高分辨率透射电镜(HRTEM)、Brunauer-Emmett-Teller(BET)、塔菲尔(Tafel)、线性扫描(LSV)、光电转化效率(IPCE)、紫外-可见漫反射光谱(UV-Vis-DRS)等手段对催化剂进行表征.结果表明,空心球状BiVO4比表面积(10.24 m2?g-1)是无定型BiVO4(1.97 m2?g-1)的5.20倍.负载CuO后,与BiVO4形成p-n型异质结结构.其中,5%负载量的空心球状BiVO4具有最佳电化学性能,Tafel表征腐蚀电流密度(2.22μA?cm-2)为空心球状BiVO4(0.18μA?cm-2)的12.33倍,禁带宽度减小为2.30 eV.以甲苯为模型污染物研究催化剂对挥发性有机化合物(VOCs)的催化去除和矿化效果,5%CuO负载量的空心球状BiVO4光催化氧化能力最佳,可见光照6 h甲苯降解率达85.0%,矿化率达12.0%.

The sol-gel method was used for the synthesis of BiVO, hollow nanospheres by employing carbon spheres as a hard template. CuO loaded composite photocatalysts were prepared by impregnation. The catalysts were characterized by X-ray diffraction （XRD）, scanning electron microscopy （SEM）, high-resolution transmission electron microscopy （HRTEM）, Brunauer-Emmett-Teller （BET）, Tafel polarization curves （Tafel）, linear sweep voltammetry （LSV）, monochromatic incident photon to current conversion efficiency （IPCE）, and UV-Vis diffuse reflectance spectroscopy （UV-Vis-DRS）. We found that the BET surface area of the BiVO4 hollow nanospheres （10.24 m2. g-l） was 5.20 times that of the amorphous form of BiVO, （1.97 m2- g-l）. A p-n heterojunction was formed between CuO and BiVO4. Samples with 5% CuO exhibited optimal photoelectrochemical performance. They had a higher corrosion current density （12.33 times as much as that of the BiVO4 hollow nanospheres）, and a smaller band gap （2.30 eV）. Toluene was chosen as a model pollutant to evaluate the removal capacity and the CO2 mineralization rate of volatile organic compounds under visible light. The samples doped with 5% CuO exhibited optimal visible-light photocatalytic activity, with an 85.0% toluene degradation efficiency and a 12.0% mineralization rate in 6 h.