碘铈共掺杂纳米TiO_2的制备及可见光光催化性能

采用溶胶凝胶法制备了不同原料比例碘铈共掺杂纳米TiO2催化剂,运用X射线光电子能谱（XPS）,X射线衍射（XRD）,透射电镜（TEM）等检测手段对催化剂进行了初步表征.结果表明,经过450℃煅烧处理得到的TiO2、铈掺杂TiO2以及碘铈共掺杂TiO2催化剂均为锐钛矿相,掺杂的Ce和I原子可能以I—Ce—O及O—Ti—I等键合方式进入TiO2晶格内部,此外,I-Ce离子共掺杂能有效降低TiO2表面的电子-空穴对的复合.以染料罗丹明B（Rhodamine B,RhB）和无色小分子水杨酸（Salicylic acid,SA）为降解的目标化合物,发现碘铈共掺杂的最佳物质的量之比为nCe∶nI∶nTi=0.04∶0.05∶1,即I0.05Ce0.04TiO2催化剂在可见光照射下（λ〉420 nm）降解目标化合物其光化学活性明显优于单掺铈的TiO2催化剂和未掺杂的TiO2.该催化反应涉及到空穴氧化,并伴有羟基自由基（.OH）、超氧自由基（O2.-）及H2O2等氧化物种的产生.

Preparation and photocatalytic propreties of I-Ce co-doped nano TiO2

I/Ce co-doped TiO2 nanoparticles with different doping contents were prepared by sol-gel method,and characterized by XPS,XRD and TEM.The results showed that the TiO2,Ce-TiO2 and Ce-I-TiO2 catalysts were anatase after 450 ℃ calcination.Ce and I atoms possibly entered the crystal lattice to form I—Ce—O and O—Ti—I bonds.Moreover,I-Ce co-doping could efficiently decrease the recombination rate of the electron/hole pairs.The degradation of rhodamine B(RhB) and salicylic acid(SA) were used as the probe reactions to determine the optimal concentration of Ce and I.The results indicated that the optimal molar ratio was nCe: nI: nTi =0.04 ∶ 0.05 ∶ 1,and the I0.05Ce0.04TiO2 catalyst had better activity than Ce-TiO2 and TiO2 catalyst under visible light irradiation(λ>420 nm).The photocatalytic process mainly involves hole oxidation mechanism along with the formation of · OH,O·-2 and H2O2.