【摘要】 利用酸催化的溶胶-凝胶法制备了纯的和不同Pr3+掺杂量的TiO2纳米粉体.以亚甲基蓝(MB)溶液的光催化降解为探针反应,评价了它们的光催化活性.利用XRD和BET技术研究了Pr3+掺杂量和焙烧温度对TiO2纳米粉体的相结构、晶粒尺寸和表面织构特性的影响,并用XPS和SPS技术研究了Pr3+掺杂的TiO2纳米粉体的表面组成和表面光伏特性,探讨了Pr3+掺杂提高纳米TiO2的光催化活性的机制.结果表明:适量Pr3+掺杂能显著提高纳米TiO2的光催化活性.当Pr3+掺杂量为1.25%(以Pr3+/TiO2质量比计),焙烧温度为600℃时,制得粉体的光催化活性最佳.Pr3+掺杂强烈地抑制TiO2由锐钛矿相向金红石相的转变,减小晶粒尺寸,增大比表面积,增加表面羟基和吸附氧的含量,提高光生电子和空穴的分离效率,改善粉体表面的光吸收性能,上述因素均有利于光催化活性的提高.更多还原

【Abstract】 Pure and Pr³⁺-doped TiO₂ nano-powders with different doping contents were prepared by an acid-catalyzed sol-gel method using Ti（OC₄H₉）₄ and Pr（NO₃）₃ as precursors and characterized by XRD,BET,XPS and SPS techniques.The effects of Pr³⁺-doping content and calcination temperature on the photocatalytic activity for photocatalytic degradation of methylene blue（MB） in aqueous solution,phase structure,crystallite size and surface texture properties of the nano-powders were investigated.The surface composition and surface photovoltaic properties of the nano-particles were also studied.The mechanism of enhancement in their photocatalytic activity was also discussed.The results indicate that Pr³⁺-doping can enhance the photocatalytic activity of TiO₂ nano-powders as compared with pure TiO₂.1.25% Pr³⁺-doped TiO₂ nano-powders calcined at 600 ℃ for 2 h show the highest photocatalytic activity.The presence of Pr³⁺ in TiO₂ can strongly inhibit the phase transformation from anatase to rutile,and reduce crystallite size,and enlarge specific surface area,and increase the contents of both surface hydroxyl groups and adsorbed oxygen,and enhance separation efficiency of photo-generated electron-hole pairs,and improve the light adsorption properties of the particle surface as well,which result in the enhancement in the photocatalytic activity.更多还原