Tb掺杂对纳米TiO_2光催化活性的影响

以溶胶-凝胶法制备了纳米TiO2和掺杂Tb的TiO2(Tb-TiO2),用X射线衍射、示差扫描量热、热重分析、红外光谱和荧光光谱等技术对纳米TiO2和Tb-TiO2的结构进行了表征;考察了以纳米TiO2及Tb-TiO2为催化剂光催化氧化环己烷合成环己酮和环己醇的情况。表征结果表明,掺杂Tb后明显抑制了TiO2中锐钛矿相向金红石相的转变,提高了TiO2催化剂的热稳定性,晶格发生了膨胀现象,晶格膨胀可有效降低光生载流子的复合几率,减小晶粒尺寸,提高光催化活性;光催化氧化环己烷的实验结果表明,与TiO2催化剂相比,Tb-TiO2催化剂的环己烷转化率和环己酮、环己醇的选择性大幅度提高,表明Tb-TiO2催化剂的光催化活性和光催化效率提高。

Effect of Doping Tb on Photocatalytic Activity of Nano -TiO2

Nano-TiO2 and Tb doped TiO2(Tb-TiO2) photocatalysts were prepared by sol-gel method, and characterized by means of XRD, DSC, TG, IR and fluorescence spectrum(PL). Doping of Tb restrains transformation of anatase crystalline form of TiO2 contained in TiO2 to rutile, improves thermal stability of TiO2 and causes expanding of crystal lattice of TiO2,which reduces probability of photogenic charge carrier recombination. Doping of Tb also decreases the size of nano-TiO2 grain and consequently raises the photocatalytic activity of TiO2. PL spectra showed that doping of Tb to TiO2 doesn’t bring about new luminescence phenomena but only strengthens intensity of PL spectrum. Photocatalytic-oxidations of cyclohexane to cyclohexanone and cyclohexanol over TiO2 and Tb-TiO2 catalysts as probe reaction were investigated. Tb doped TiO2 catalyst shows higher activity and selectivities to cyclohexanol and cyclohexanone than sole TiO2.