共沉淀法制备多孔 TiO2／Al2O3纳米复合材料及其光催化性能研究

摘要

The porous TiO2/Al2 O3 nanocomposites with high specific surface areas and high thermal stability had been successful-ly synthesized by a coprecipitation method from precursor solutions derieved from titanium tetrachloride and trimethylaluminum. The products were analyzed by XRD,SEM,N2 absorption-desorption isotherms testing and photocatalytic testing.The effect of different calcination temperatures on the specific surface areas,porosity structures,degree of crystallinity and crystal phase com-position of the products were investigated.The mechanism of the effect of calcination temperatures on photocatalytic performance had been elaborately elucidated.The results show that the sample has high BET specific surface area of 50.9 m2/g even calcined at a high temperature of 800 ℃,and the highly connected porosity structures of the sample could also be well preserved.The ad-dition of alumina can not only promote the transformation temperature of anatase TiO2 to rutile TiO2 by 200-300 ℃ but also stabi-lize porosity structure of the material.The sample calcined at 800 ℃ has the best photocatalytic performance.Its photocatalytic degradation rate of RhB can reach 81.7% in 50 min under UV-visible light irradiation.%以 TiCl4为钛源，Al（CH3）3为铝源，采用共沉淀法制备出了具有高比表面积且热稳性良好的多孔 TiO2／Al2 O3纳米复合材料。对合成的材料进行了 XRD、SEM、氮气吸附脱附等温曲线测试及光催化性能测试。分析了焙烧温度对材料的结晶度和晶相组成、孔尺寸和比表面积的影响，并重点考察了焙烧温度对光催化性能的影响机制。制备出的材料在800℃高温焙烧后，比表面积仍高达50．9 m2／g，同时其具有的高度连通的三维孔道结构也能很好地保持。研究发现复合材料中氧化铝的加入将氧化钛由锐钛矿向金红石的相转变温度提高了200～300℃，同时对材料的孔结构也有稳定作用。其中800℃焙烧的样品的光催化性能最好，紫外加可见光照射下，50 min 内对罗丹明 B 染料的降解率达81．7％。