La2O3掺杂TiO2光催化剂的制备和性能

采用溶胶-凝胶法制备了La2O3掺杂TiO2纳米光催化剂，并通过XRD、TEM、BET和XPS等手段进行了表征．掺入La2O3后，阻止了TiO2从锐钛矿晶型向金红石晶型的转变，使TiO2的粒径减小，比表面积增大．以甲基橙为光催化降解反应模型化合物，考察了光催化剂的活性．测定了甲基橙在纯TiO2和La2O3掺杂TiO2光催化剂上的吸附常数．考察了pH、H2O2对降解性能的影响．讨论了光催化活性与催化剂性质的关系．

Preparation and Properties of La 2O3 doping TiO2 Photocatalyst

La_2O_3-TiO_2 samples were prepared by sol-gel process and characterized by means of XRD, TEM, BET, and XPS. It has been shown that with the doping of La_2O_3 the particle diameter of La_2O_3-TiO_2 samples decreased, the specific surface area increased, and the crystal phase transformation of TiO_2 from anatase to rutile is prevented. Using the photocatalytic degradation of methyl orange as a model reaction, activity of prepared photocatalysts was investigated in TiO_2 and La_2O_3-TiO_2 nano-power suspension irradiated by high-pressure mercury lamp. As a result, the addition of La_2O_3 to TiO_2 notably enhanced its photocatalytic activity. The adsorption constants of methyl orange on the Lanthanum Oxide doped catalysts and the nonmodified TiO_2 catalyst were evaluated. The effects of H_2O_2 and pH of the methyl orange on the degradation ratio also were investigated. The optimum loading amount of La is 1% of Ti (molar ratio). Moreover, the relationship between photocatalytic activity and the properties of the samples has been discussed.