掺杂Yb的TiO2光催化剂的制备和性能

采用溶胶-凝胶法制备了Yb掺杂TiO2纳米光催化剂,并通过XRD和BET等手段进行了表征.以对苯二甲酸作为探针分子,结合化学荧光技术研究了光催化剂表面羟基自由基的生成;并以苯酚为光催化降解反应模型化合物,考察了光催化剂的活性.测定了苯酚在TiO2和Yb掺杂TiO2光催化剂上的吸附常数.结果表明:Yb掺杂使TiO2的粒径减小,比表面积增大,同时导致羟基自由基的生成速率增大.Yb掺杂有利于反应底物在催化剂表面的吸附,Yb的最佳掺入量为Yb/Ti摩尔比=0.8%.

Preparation and Properties of Yb Doped TiO2 Photocatalysts

Yb/Ti samples were prepared by sol-gel process and characterized by means of XRD and BET.After doped with Yb,the particle diameter of catalyst was decreased,the specific surface area was increased,the formation rate of hydroxyl radical on the catalyst was increased,and the catalytic activity was improved.Using phenol as the model compound of the photocatalytic degradation reaction,the activity of the prepared photocatalysts was investigated in suspension irradiated by high-pressure mercury lamp.The hydroxyl radical produced in the supernatant of the irradiated catalyst suspension containing terephthalic acid were also investigated by measuring the fluorescence derived by the reaction with terephthalic acid.As the result showed,the addition of Yb to TiO_2 notably enhanced its photocatalytic activity.The adsorption constants of phenol on the Yb doped catalysts and the nonmodified TiO_2 catalyst were evaluated,and the result showed the adsorption of phenol on the Yb/Ti catalysts was improved.The optimum loading amount of Yb ion is 0.8%(molar ratio).