BiOCl/TiO_(2)的氯化改性及其新式光生自由基催化反应  

The new free radical reaction of chlorinated BiOCl/TiO_(2)

作　　者：王磊[1,2] 韩浩[2] 朱凌甫[3] 彭猛 康健 王德生[2] 许嘉钰[1] WANG Lei;HAN Hao;ZHU Lingfu;PENG Meng;KANG Jian;WANG Desheng;XU Jiayu(Tsinghua University,School of Environment,Beijing 100084;Research Institute of Chemical Defense,State Key Laboratory of NBC Protection for Civilian,Beijing 102205;Beijing University of Chemical Engineering,College of Chemical Engineering,Beijing 100029)

机构地区：[1]清华大学,环境学院,北京100084 [2]防化研究院,国民核生化灾害防护国家重点实验室,北京102205 [3]北京化工大学,化学工程学院,北京100029

出　　处：《环境科学学报》2021年第7期2758-2765,共8页Acta Scientiae Circumstantiae

基　　金：国家大气攻关项目(No.DQGG0302-04)。

摘　　要：采用溶胶凝胶法制备了BiOCl/TiO_(2)复合催化剂,透射电镜(TEM)照片显示,两种半导体分布均匀、相互连接,形成的异质结可以为电子传导提供有效通道.经过氯化处理的复合材料具备更强的光催化能力,在紫外光条件下对苯的降解率达到90%,是原BiOCl/TiO_(2)的2倍、纯TiO_(2)的10倍.本文利用X射线光电子能谱、红外光谱和电子顺磁共振,对表面氯化的机理进行研究.结果表明,氯元素以Ti—Cl的方式吸附在催化剂表面,在光照条件下光生空穴夺取一个电子,使其生成氯自由基,进而配合超氧、羟基,构成一种新型的三自由基光催化体系,使催化降解能力大幅提升.最后,利用实验方法得到了光生氯自由基的直接证据,并构建了该体系的光催化反应机理.In this article,the BiOCl/TiO_(2) composite has been successfully prepared via a sol-gel method and then modified by surface chlorination.According to the TEM images,two components were uniformly dispersed and connected to each other,which facilitated the transfer of photo-generated carriers.Under the UV light irradiation,the BiOCl/TiO_(2) exhibited good photocatalytic activity and stability for gas-phase benzene oxidation and the surface chlorination would further enhance its performance.About 90%degradation was achieved over chlorinated BiOCl/TiO_(2),which was twice as original BiOCl/TiO_(2) and ten times compared to bare TiO_(2).The prepared composites have been characterized by electronic chemistry station,Fourier transform infrared spectrometry(FT-IR),X-ray photoelectron spectroscopy(XPS)and electron paramagnetic resonance(EPR)to explore the outstanding photocatalytic activity.As confirmed by XPS and FT-IR,the Cl was chemically adsorbed on the surface of catalyst(Ti-Cl),which would lead to a new mechanism for photocatalysis.Under the UV light irradiation,besides·OH and·O_(2)^(-) radicals,the photocatalytic reaction was also driven by photo-generated·Cl radicals,which was confirmed by EPR analysis.Hence,the photocatalytic activity was significantly enhanced by synergistic effects of three radicals.

关 键 词：BiOCl/TiO_(2) 光催化 氯自由基 

分 类 号：X131[环境科学与工程—环境科学]