可见光响应Pt沉积La_2O_3/TiO_2制备及其对甲苯的光热催化去除

Preparation of Visible Light Response Pt-doped La_2O_3/TiO_2 and Thermo-photocatalytic Degradation of Toluene

以钛酸四丁酯和硝酸镧为原料,采用溶胶—凝胶法制备La2O3/TiO2,通过光沉积法在La2O3/TiO2表面负载纳米Pt粒子.采用XPS、FTIR、XRD、DRS、TEM和低温氮物理吸附对光催化剂的晶体结构、光谱特征和表面结构进行表征.考察了催化剂在可见光下对甲苯的去除性能和温度对催化剂去除甲苯的影响.结果表明,沉积的Pt以单质和吸附氧的形式存在,其中以吸附氧的形式为主.Pt的掺入没有引起TiO2相结构的变化,减小了晶粒尺寸并增大了催化剂的比表面积.纳米Pt均匀地分布在La2O3/TiO2上,尺寸分布比较均一,大约为5～10nm.Pt-La2O3/TiO2的表面羟基官能团伸缩振动明显增强,比TiO2和La2O3/TiO2具有更高的可见光催化活性.Pt-La2O3/TiO2对甲苯的降解率,随着温度的升高而增大,产生了与光催化作用平行的热催化作用.气相甲苯光热催化过程不是光催化与热催化的简单叠加,而是存在协同作用.

Pt-La2O3/TiO2 photocatalyst was prepared by Sol-Gel and photodeposition methods using Ti（OBu）4 and La（NO）3.6H2O as raw material.The catalyst was characterized by XPS,FTIR,XRD,DRS,TEM,and N2（77K） adsorp-tion.The performance of photocataltic in the removal of toluene under visible light and the influence of temperature on removal of toluene were investigated.The results showed that doped-Pt existed as the forms of single Pt and oxy-gen-adsorption.Pt loading had no influence on the phase composition of TiO2,but decreased TiO2 particle size and in-creased the surface area.Nano-Pt was uniformly dispersed on La2O3/TiO2 with diameter of 5？10 nm.Pt-La2O3/TiO2 has much more hydroxyl group than TiO2 and La2O3/TiO2.The rate of photocatalytic oxidation gaseous toluene on Pt-La2O3/TiO2 increased with the temperature increasing,and thermal catalytic reaction taken place in parallel with photocatalytic oxidation reaction.There is a synergetic effect between photocatalysis and thermal catalysis in the thermo-photocatalysis degradation of toluene.