稀土金属Ce^(3+)掺杂ZnO材料的光催化机理  

Photocatalytic Mechanism of Rare Earth Metal Ce^(3+) Doped ZnO Materials

作　　者：李佩欣 辛浪 宋佳 杨爱云 崔娟[1] 殷春浩[2] LI Peixin;XIN Lang;SONG Jia;YANG Aiyun;CUI Juan;YIN Chunhao(Department of Basic Courses, Xi’an Traffic Engineering Institute, Xi’an 710300, China;School of Mateials and Physics, China University of Mining and Technology, Xuzhou 221116, China)

机构地区：[1]西安交通工程学院公共课部,西安710300 [2]中国矿业大学材料与物理学院,徐州221116

出　　处：《人工晶体学报》2021年第9期1723-1728,共6页Journal of Synthetic Crystals

基　　金：西安交通工程学院中青年基金(21KY-03)。

摘　　要：通过溶胶凝胶法制备了光催化活性更高的Ce∶ZnO复合粉体光催化材料,并采用X射线衍射(XRD)、电子顺磁共振(EPR)、紫外可见光谱(UV-Vis)技术对所制备的粉体样品的晶体种类及结构、自由基种类及含量、光催化效率进行表征分析。复合样品的X射线衍射测试结果显示,随着掺杂浓度的增加,先后检测到CeO_(2)的(111)和(200)晶面特征峰,且衍射峰强度逐渐增强。此外,适量的掺杂(c(Ce^(3+))=2%)可减小ZnO晶体的晶粒尺寸。电子顺磁共振测试结果显示,Ce∶ZnO复合光催化材料中存在三类自由基,分别是Zn-H络合物、正一价氧空位、CeO_(2)表面吸附的超氧根离子。紫外可见光谱测试表明,适量的掺杂可有效提高ZnO催化剂的光催化活性,综合分析显示,ZnO光催化活性提高的主要原因是Ce^(3+)的掺入使得材料中电子数量增多,进而提高了活性自由基·O^(-)_(2)的数量。本文通过EPR技术和XRD衍射技术,成功表征了Ce^(3+)掺杂对ZnO材料中自由基种类合成的影响过程,并结合UV-Vis技术,对Ce∶ZnO复合材料光催化降解甲基橙的过程中的电子转移过程作出了合理的解释。The photocatalytic materials of Ce∶ZnO composite powder with higher photocatalytic activity was prepared by sol-gel method.The crystal type and structure,free radical type and content,and photocatalytic efficiency of the prepared powder samples were characterized by X-ray diffraction,electron paramagnetic resonance and ultraviolet visible spectroscopy.X-ray diffraction test results of the composite samples show that with the increase of doping concentration,the characteristic peaks of(111)and(200)crystal plane of CeO_(2) are detected successively,and the intensity of the diffraction peaks gradually increases.In addition,appropriate doping(c(Ce^(3+))=2%)can reduce the grain size of ZnO crystal.The results of electron paramagnetic resonance test show that there are three kinds of free radicals in Ce∶ZnO composite photocatalytic material,which are Zn-H complex,positive monovalent oxygen vacancy and superoxide ions adsorbed on the surface of CeO_(2).Ultraviolet visible test shows that appropriate doping(c(Ce^(3+))=2%)could effectively improve the photocatalytic activity of ZnO catalyst.Based on the analysis of electron paramagnetic resonance and ultraviolet visible test results,the doping of Ce^(3+)provides more electrons for O_(2) when it is converted to Ce4+,on the other hand,the generated CeO_(2) has a strong oxygen absorption capacity.The photocatalytic activity of ZnO is improved by increasing the utilization rate of O_(2) and generating more active free radicals.In the experiment,the influence process of Ce^(3+)doping on the synthesis of free radicals in ZnO materials was successfully characterized by electron paramagnetic resonance and X-ray diffraction techniques,and the electron transfer process in the photocatalytic degradation of methyl orange by Ce∶ZnO composites was reasonably explained by ultraviolet visible technology.

关 键 词：ZnO 电子顺磁共振 Ce^(3+)掺杂 光催化活性 电子转移 自由基 

分 类 号：O643.36[理学—物理化学] O644.1[理学—化学]