Ag/ZnO-Bi_2O_3复合催化剂的制备及其光催化性能研究

Preparation and Photocatalytic Properties of Ag/ZnO-Bi_2O_3 Composite Catalysts

以Zn(Ac)2·2H_2O、Bi(NO3)3·5H_2O、硝酸银为原料,柠檬酸为络合剂,聚乙二醇400与去离子水为溶剂,空气氛下高温煅烧制备了Ag/Zn O-Bi2O3复合催化剂,并采用X射线衍射、扫描电镜、透射电镜和紫外-可见光漫反射吸收光谱对产物进行了表征。结果表明,掺杂Ag和Bi2O3显著降低了Zn O的禁带宽度,达到2.93 e V,吸收光谱红移至423 nm处;当原料中Zn∶Bi∶Ag元素的摩尔比为1∶0.1∶0.25时,制备的Ag/Zn O-Bi2O3紫外光下催化降解甲基橙溶液性能较佳,降解率可达95%;同时发现复合催化剂与双氧水具有协同效应,可将达到相同降解率时间缩短到2 h。

Using Zn（Ac） 2· 2H2O, Bi （ NO3 ）3· 5H2O and AgNO3 as raw material, citric acid as complexing agent, polyethylene glycol 400 and deionized water as solvent, Ag /ZnO-Bi2O3 composite catalysts were prepared by the high temperature calcinations under air atmosphere, and the products were characterized by X-ray diffraction （ XRD ） , scanning electron microscopy （ SEM ） , transmission electron microscopy （ TEM） and Ultraviolet-Visible diffuse reflection spectrum. The results show that the doping of Ag and Bi2O3 significantly reduced the forbidden band width of ZnO to 2. 93 eV, and absorption spectra of the products are red shifted to the light spectrum 423 nm. When the molar ratio of raw materials are Zn ：Bi： Ag = 1：0.1：0.25,as-prepared Ag /ZnO -Bi2O3 composite catalysts attain the best performance on the catalytic degradation of methyl orange under ultraviolet light, and degradation rate is up to 95 %. In addition, synergistic effect of composite catalyst and hydrogen peroxide was found, and the time to achieve the same degradation rate was shortened to 2 h.