纳米SiO_2/TiO_2复合光催化剂的可控制备及应用研究

Controllable preparation of nano SiO_2/TiO_2 composite light catalyst and application research

以钛酸四丁酯、正硅酸乙酯、醋酸及无水乙醇等试剂为原料,分别采用水热合成法和溶剂热法制备出了纳米SiO_2/TiO_2的复合光催化剂,通过SEM、XRD、BET等表征分析探究其物相组成及微观结构,并在氙灯照射的条件下测定所制得复合光催化剂对亚甲基蓝的光催化降解能力,探究不同硅钛比对复合光催化剂催化效果的影响。结果表明:采用无水乙醇为溶剂,Si与Ti的摩尔比为1:1的条件下制得的复合光催化剂具有较大的比表面积,为387.9634 m^2/g,孔隙分布适度。室温下反应2 h,亚甲基蓝降解率高达99%以上,其光催化性能优于P25纳米TiO_2光催化剂。Si与Ti的摩尔比为1:1时复合光催化剂的催化活性高于其它摩尔比的光催化剂,采用溶剂热法制得的复合光催化剂的催化活性优于水热合成法。复合光催化剂的降解能力与样品的组成、合成的条件及颗粒大小均密切相关。

Using tetrabutyl titanate,ethyl orthosilicate,acetic acid,anhydrous ethanol and other reagents as raw materials,the thesis respectively adopte hydrothermal method and solvethermal method to produce the composite photocatalyst of nano SiO_2/TiO_2 composite photocatalyst.Through Characterization analysis of SEM,XRD,BET,etc,we explore the phase composition and microstructure and then measure the catalytic degradation ability of the achieved composite photocatalyst effecting on The light of methylene blue under the condition of xenon lamp irradiation.By this method,the thesis explore the influence of different molar ratio of Si and Ti in composite photocatalyst on photocatalytic activity.The result show that adopting anhydrous ethanol as solvent,composite photocatalyst that produced on the condition of the molar ratio of Si and Ti being 1:1 has large specific surface area,which is 387.9634 m^2/g,and the distribution of the pores are moderate.Under the condition of room temperature,when the reaction lasts 2 h,the degredation rate of methylene blue reaches over 99%,which is better than that of P25 nano TiO_2 Photocatalyst.The catalytic activity is the best when the molar ratio of Si and Ti comes to 1:1.The catalytic activity of the photocatalyst synthesized via solvethermal method is better than that of hydrotnermal method.The degradation ability of composite photocatalyst is closely related to the composition of the samples,synthesis conditions as well as the size of particle.