数据挖掘在稀土掺杂纳米TiO2结构与光催化活性关系中的应用

摘要

采用溶胶-凝胶法制备了不同稀土、不同掺杂量的纳米TiO2光催化剂,对其进行了XRD分析,并在紫外光源下对其降解甲基橙的光催化活性进行了测定；并藉此建立了构效关系,进行了数据挖掘.结果表明,随着掺杂量( Ln/Ti摩尔比率,Ln=Eu、Ce、Y)的增加,稀土掺杂改性的纳米TiO2的衍射峰逐渐宽化、强度逐渐减弱；最佳掺杂量为0.05％,掺杂量过多时,光催化效果反而下降；用多元逐步回归分析挖掘数据样本间的联系,发现结构参数(晶胞参数a、晶格畸变(ε)、晶粒尺寸D)与光催化剂的表现速率常数k间存在良好的相关性,其关系式为:k=-57.6879+37.5097a+68.3791(ε)+0.0193D-29.6588(ε)2,相关系数大于0.99,说明该模型具有良好的稳定性和预测能力.%Rare-earth doped nano-TiO2 photocatalysts with different rare-earth ions and different doping a-mounts were prepared by sol-gel method. The products were characterized using X-ray diffraction(XRD), Their photocatalytic activities were evaluated by photodegradation of methyl orange in water under UV light irradia-tion. Structure-effective relationship of rare-earth doped nano-TiCX photocatalysts was established and data min-ing was carried out. It was demonstrated that the increase of doping amount(molar fraction of Ln/Ti,Ln=Eu, Ce,Y) caused the XRD peaks to broaden and weaken. And the optimal doping amount was 0. 05%. A non-linear mathematic model was identified by analyzing the experimental results through multiple stepwise regress. Then the relationship between XRD data and the rate constant(k) of the photocatalysts was studied. There was a gen-eral linear relationship between them. The equation could be expressed as follows:k=-57. 6879 + 37. 5097a + 68. 3791ε+0. 0193D- 29. 6588ε2. The correlation coefficient was larger than 0. 99. It had been demonstrated that the model had good stability and predictability.