Sm掺杂对TiO2薄膜光催化性能的影响

 采用溶胶-凝胶法、浸渍-提拉法制备了不同形式和不同含量Sm掺杂的锐钛矿晶型TiO2的光催化剂薄膜. 采用X射线衍射、UV-Vis光谱及电化学实验对所制得的TiO2光催化剂薄膜进行了表征,并通过甲基橙溶液的光催化降解实验评价了其光催化活性. 结果表明,与未掺杂的TiO2薄膜相比,Sm掺杂的TiO2薄膜的UV-Vis吸收光波长向长波方向移动,并且光照开路电压也相应提高; 适量Sm掺杂可以明显提高TiO2薄膜的光催化活性,最佳Sm掺杂量为x(Sm3+)=0.5%; 在各种掺杂形式中以表层Sm掺杂的Sm-TiO2(S)薄膜的光催化活性最好. 讨论了Sm掺杂提高TiO2薄膜光催化活性的机理.

Effect of Sm3+ Doping on Photocatalytic Properties of TiO2 Thin Films

Sm 3+-doped TiO 2 thin films with different doping modes and Sm contents were prepared by the sol-gel dip-coating technique and characterized by X-ray diffraction, UV-Vis spectroscopy and electrochemical experiment. The photocatalytic activity of the TiO 2 thin films was evaluated by the photocatalytic degradation of methyl orange. XRD results showed that both pure TiO 2 and Sm 3+-doped TiO 2 thin films were of anatase type and oriented predominantly to the (101) plane, and no crystallographic planes of Sm 2O 3 were identified in Sm 3+-doped films. This is due to the low content of the Sm 3+ dopant and the possible incorporation of Sm 3+ into the anatase lattice. A shift of the UV-Vis absorption towards longer wavelength was observed, which indicated a decrease in the band-gap of TiO 2 upon Sm 3+ doping. The electrochemical experiment showed that the open circuit photo-potential of Sm 3+-doped TiO 2 thin films increased compared with the un-doped TiO 2 thin film. The photocatalytic experiment results showed that the Sm 3+ doping content and doping mode were the important factors that affected the photocatalytic activity of TiO 2 thin films. The doping of appropriate amount of Sm improved the photoctalytic activity obviously, and the optimum Sm 3+ content was about 0 5%. The surface doping thin film (Sm-TiO 2(S)) showed the highest catalytic activity. The possible mechanism for the enhancement of the photocatalytic activity of the TiO 2 thin films by Sm 3+ doping was discussed based on PN junction theory.