镧和铁掺杂纳米TiO_2的制备及其光催化性能

采用溶胶-凝胶法,制备了TiO2、Fe3+/TiO2、La3+/TiO2、Fe3+-La3+/TiO2光催化剂。考察了焙烧温度、焙烧时间和掺杂离子的种类和用量对催化剂用于紫外光催化降解亚甲基蓝性能的影响。制备纯TiO2、Fe3+/TiO2和La3+/TiO2的适宜焙烧温度分别为673,673和773 K,适宜焙烧时间为120min(TiO2)、180min(La3+/TiO2)。La3+/TiO2中La3+的适宜掺杂量为1.0%,Fe3+/TiO2中Fe3+的适宜掺杂量为0.04%,Fe3+-La3+/TiO2中,当La3+的掺杂量为1.0%时,Fe3+的适宜掺杂量为0.02%,相应的脱色率为99.83%,99.51%,98.73%。当掺杂量适当时,4种催化剂用于紫外光催化降解亚甲基蓝的活性次序为:La3+/TiO2>Fe3+/TiO2>Fe3+-La3+/TiO2>TiO2。根据XRD结果,由谢乐公式估算出所得光催化剂为纳米粒子。

Preparation of TiO2 doped Fe3+ ,La3+ and its photocatalytic performance

Photocatalyst TiO2,Fe3 /TiO2,La3 /TiO2 and Fe3 -La3 /TiO2 were prepared by sol-gel method and its decolorization performance of methylene blue under ultraviolet were investigated.The proper conditions in preparing doped TiO2 were obtained by investigating the effects of doped matter and their amount,roasting temperature and roasting time on the performance of catalysts.The proper roasting temperature was 673 K(TiO2),673 K(Fe3 /TiO2) and 773 K(La3 /TiO2) respectively;the roasting time was 120 min(TiO2),180 min(La3 /TiO2).The proper Fe3 doped amount in Fe3 /TiO2 was 0.04%;the proper La3 doped amount in La3 /TiO2 was 1.0%;the proper Fe3 doped amount in Fe3 -La3 /TiO2 which was doped 1.0% La3 was 0.02%,the corresponding decolorization performance are 99.83%,99.51%,98.73% respectively.The XRD results show that the obtained photocatalyst were composed of anatase.The order of photocatalytic activities of the photocatalysts from high to low was:La3 /TiO2> Fe3 /TiO2>Fe3 -La3 /TiO2>TiO2.According to Scherrer equation,the crystal sizes of La3 /TiO2,Fe3 /TiO2,Fe3 -La3 /TiO2 and TiO2 were evaluated in nanometer.