不同煅烧温度制备的Mn、N掺杂TiO2光催化性能研究

Study on the photocatalytic properties of Mn, N-doped TiO_2 prepared at different calcination temperatures

以MnSO4·H2O为锰源,尿素为氮源,采用溶胶-凝胶法制备不同锻烧温度的纯TiO2、Mn-TiO2及Mn-N-TiO2光催化剂,利用X射线衍射、紫外-可见光漫反射光谱及电子自旋共振等技术对样品形貌和结构进行表征,并以罗丹明B的光催化降解为模型反应,考察不同锻烧温度对其光催化活性的影响.结果表明,Mn、N成功掺入TiO2后,有利于提高光催化剂的热稳定性,抑制锐钛矿相向金红石相转化,且光吸收拓展到可见光区域.Mn、N共掺杂样品比单Mn掺杂样品具有更高的光催化活性,400℃下锻烧的Mn-N-TiO2在可见光下对罗丹明B的降解具有最高的光催化活性,光照2h降解率达到100%.高温锻烧Mn-N-TiO2和Mn-TiO2样品在紫外光照射30min后对罗丹明B的降解率在90%以上.

Abstract ： A series of Mn-doped TiO2 , Mn-N-codoped TiO2 and pure TiO2 nanocrystal photocatalysts were prepared by a simple sol-gel method at different calcination temperatures. The catalysts were characterized by X-ray diffraction, UV-vis diffuse reflectance spectroscopy and ESR techniques. The photocatalytic activities of the samples calcined at different temperatures were evaluated by rhodamine B degradation. Mn and N co-doping improved thethermal stability of TiO2 and inhibited the phase transformation from anatase to rutile. The light absorption of the samples extended to visible range after Mn-N co-doping. Mn-N-codoped TiO2 showed a higher photocatalytic activity than Mn-doped TiO2. The Mn-N-codoped TiO2 calcined at 400℃ exhibited the highest photocatalytic activity under visible light irradiation and 100% rhodamine B was degraded after 2 h. The photocatalytic degradation efficiency of Mn-N-codoped TiO2 and Mn-doped TiO2 calcined at high temperature was above 90% under UV light irradiation for 30 min.