La_2O_3／TiO_2／SO_4^(2-)纳米光催化剂的制备和性能

Preparation and Properties of La_2O_3/TiO_2/SO_4^(2-) Nano-Photocatalysts

采用溶胶-凝胶-浸渍法制备了La2O3／TiO2／SO42-纳米光催化剂。采用X射线衍射和BET比表面积测试法对纳米光催化剂的晶型和比表面积进行了表征。以甲基橙溶液为光催化降解反应模型化合物,考察了纳米光催化剂的催化活性。实验结果表明,La2O3的掺杂使TiO2的粒径减小,比表面积增大,La2O3的最佳掺杂量(相对于TiO2的摩尔分数)为1．00％,La2O3／ TiO2(x(La2O3)=1．00％)为纳米光催化剂时,甲基橙的脱色率达到75．8％(光照60min);SO42-的负载也使TiO2的粒径减小, 比表面积增大,浸渍液H2SO4的浓度对纳米光催化剂的催化活性有一定的影响,H2SO4的最佳浓度为0．4 mol／L,TiO2／SO42- (c(H2SO4)=0．4 mol／L)为纳米光催化剂时,甲基橙的脱色率达到83．2％(光照60 min);掺杂La2O3和负载SO42-使TiO2纳米光催化剂的催化活性显著提高,La2O3／TiO2／SO42-(x(La2O3)=1．00％,c(H2SO4)=0．4mol／L)为纳米光催化剂时,甲基橙的脱色率达到91．7％(光照60min)。

La2O3/TiO2/SO4^2- nano-photocatalysts were prepared by sol-gel-impregnation and characterized by means of XRD and BET. Activities of prepared nano-photocatalysts were evaluated by decolorizing methyl orange solution as model compound to photocatalytic degradation under irradiation of high-pressure mercury lamp. When La2O3 was doped to TiO2, particle diameter of nano-photocatalyst decreased and its specific surface area increased. Under optimal addition amount of La2O3 into TiO2 1.00% （mole fraction）, decolorizing rate of methyl orange on La2O3/TiO2 nano-photocatalyst was 75.8 % after 60 min irradiation. When SO4^2- was loaded on catalyst, its particle diameter also decreased and specific surface area increased. H2SO4 concentration affected activity of nano-photocatalyst. At optimal concentration of H2SO4 （0.4 mot/L） 83.2% of methyl orange could be decolorized after irradiated for 60 min. Addition of both La2O3 and SO4^2- into TiO2 notably enhanced photocatalytic activity of the catalyst and decolorizing rate of methyl orange on La2O3/TiO2/SO4^2- （ x （ La2O3 ） = 1.00% ,c（H2SO4） =0.4 mol/L）could reach 91.7% after irradiation for 60 min.