硅藻土负载La3+/TiO2光催化剂的制备及其光催化性能

摘要

Using tetrabutyl titanate as the precursor and diatomite as the carrier,TiO2/diatomite photocat-alysts were prepared by sol-gel method,and then La3+/TiO2-diatomite photocatalysts were synthesized by using lanthanum nitrate as lanthanum source and the impregnation-calcination method. The as-prepared catalysts were characterized by X-ray powder diffraction and scanning electron microscope. Using methyl-ene blue as simulated organic wastewater,the effects of Ti/Si molar ratios and La3+ doping amounts on photocatalytic performance of the photocatalysts were studied. The results showed that the diatomite could improve the dispersity of TiO2 and reduce the crystal size of TiO2 . In addition,the transformation of ana-tase-to-rutile phase could be restrained when diatomite was doped into TiO2 . Under the condition of n(Ti):n(Si)=1:1,La3+ doping mass fraction 1%,and calcination temperature 550 ℃,La3+/TiO2-diatomite photocatalyst exhibited the best photocatalytic activity. The degradation rate of methylene blue reached 99. 9% under the continuous irradiation of UV light for 180 min.%以钛酸四丁酯为前驱体，硅藻土为载体，采用溶胶-凝胶法制备TiO2/硅藻土负载型光催化剂。以硝酸镧为镧源，采用等体积浸渍-焙烧法制备La3＋/TiO2-硅藻土光催化剂。通过XRD和SEM对制备的催化剂进行表征，以亚甲基蓝溶液模拟有机废水，考察n（ Ti）：n（ Si）及La3＋掺杂量对催化剂光催化性能的影响，结果表明，硅藻土可提高TiO2分散性，降低TiO2晶粒尺寸，并抑制其由锐钛矿相向金红石相的转变。在n（ Ti）：n（ Si）=1：1、焙烧温度550℃和La3＋掺杂质量分数1%条件下，La3＋/TiO2-硅藻土光催化剂的光催化活性较好，紫外光连续照射180 min，亚甲基蓝降解率可达99.9%。