摘要
为提高氮掺杂二氧化钛的可见光响应及反应效率,以尿素为氮源,硅胶为负载剂,采用溶胶-凝胶法制备了二氧化硅负载氮掺杂二氧化钛粉末,再采用等体积浸渍法将二氧化锰负载在上述催化剂上,经过烘干、焙烧制得具有可见光响应的复合型光催化剂;利用TEM、SEM、XRD、XPS等方法对制备的复合型光催化剂进行了表征,在可见光照射下对复合型光催化剂的光催化活性进行了测试,并考察了氮的掺杂量和焙烧温度对其光催化活性的影响。试验结果表明:改性后的复合型光催化剂光响应范围由紫外光区拓展到可见光区,在降解甲基橙的试验中表现出良好的可见光催化活性;通过对其光催化反应机理的探讨及处理效果的分析,负载的二氧化锰催化产生的O_2可作为良好的电子捕获剂而提高反应效率;随着氮掺杂量的减少、焙烧温度的提高,复合型光催化剂的可见光催化活性减弱。
In order to improve the visible light response and reaction efficiency of nitrogen-doped TiO_2,this paper prepares powder of nitrogen-doped TiO_2 supported on SiO_2 by using the sol-gel method with urea as the nitrogen source and silica gel as the load agent,then loads MnO_2 on the forenamed catalyst by using the incipient-wetness impregnation method,and after drying and roasting processes,prepares the composite photo-catalyst which responds to the visible light.The paper characterizes the prepared composite photocatalysts by TEM,SEM,XRD and XPS,and tests the photo-catalytic activity of the composite photo-catalysts in the visible-light region and investigates the influence of nitrogen content and calcination temperature on the photo-catalytic activity.The experimental results show that the light response range of the modified composite catalyst expands from UV to visible-light region,which results in a high visible-light photo-catalytic activity in the degradation of methyl orange.Through the analysis of the mechanism and the treatment effect of photo-catalytic reaction,catalytically generated O_2 by loaded MnO_2 can serve as a good electronic capture agent to improve the efficiency of reaction.With the reduction of nitrogen content,and the increase of calcination temperature,the visible-light photo-catalytic activity of the composite catalyst weakens.
出处
《安全与环境工程》
CAS
2016年第2期45-49,共5页
Safety and Environmental Engineering
