过渡金属离子掺杂纳米TiO2的相变与光催化活性

采用溶胶-凝胶法制备了掺杂Mo⁶⁺、Cr³⁺、Fe³⁺的改性纳米TiO₂光催化剂，并分别在550℃和580℃下对其进行了热处理，考察了热处理温度对掺杂纳米TiO₂相变和光催化活性的影响.通过光催化降解染料罗丹明B实验，对在不同热处理温度下Mo⁶⁺、Cr³⁺、Fe³⁺改性以及不同Mo⁶⁺掺杂量的TiO₂光催化活性进行了评价，发现掺杂离子对TiO₂光催化活性的影响与其对TiO₂相转变的作用是一致的，即抑制相转变的同时也提高了光催化活性.实验结果也进一步表明，Mo⁶⁺掺杂量为0.05％（摩尔分数）时的TiO₂具有最佳光催化活性.

Transformation and photocatalytic activities of nano-sized TiO2 doped by transition metal ions

The TiO₂ nanoparticles doped by Mo⁶⁺, Cr³⁺ and Fe³⁺ ions with the ion concentration of 0.05%（mol） were prepared by the Sol-Gel method at calcination temperatures of 550℃ and 580℃, and characterized by XRD, BET and FT-IR.The results showed that Mo⁶⁺ ion doping efficiently inhibited the phase transformation of TiO₂ at different temperatures, while Cr³⁺ and Fe³⁺ ion doping played a reverse effect at 550℃ and 580℃ respectively, which might be caused by the disparate status of doping ion in the titania crystals due to different calcination temperatures.The photocatalytic decomposition of dye rhodamine B was utilized to evaluate the influences of calcination temperature and ion concentration on the photocatalytic activities of doped nano-sized TiO₂.It was found that the influences of ion doping on the photocatalytic activities of titania were consistent with the influences of ion doping on phase transformation.The TiO₂ doped by Mo⁶⁺ with the ion concentration of 0.05%（mol） showed the highest photocatalytic activities.