掺杂TiO2介孔材料的合成与表征

基于溶胶-凝胶过程, 以非表面活性剂有机小分子三乙醇胺为模板剂, 合成了TiO2及Fe3+/V5+-TiO2介孔材料. 利用XRD, TEM, BET, UV-Vis DRS等手段表征了材料的结构、形貌、比表面积、孔径分布及吸光性能. 研究结果表明, 用乙醇萃取法脱除模板剂可形成具有蠕虫状孔道结构的TiO2介孔材料, 而利用焙烧法在450 ℃脱除模板剂时可引起孔道的塌陷. 掺杂Fe3+或V5+可稳定材料的介孔结构, 适宜的掺杂摩尔分数为0.5％. 于450 ℃下焙烧后, 掺杂Fe3+/V5+的TiO2的平均孔径分别为10.5和9.6 nm, 比表面积分别达到103.59和90.80 m2/g. 相对于P25光催化剂, 掺杂Fe3+或V5+的TiO2吸光带边红移至可见光区, 说明掺杂离子在此合成过程中可有效地进入TiO2的晶格结构而引起其微观电子结构的改变.

Synthesis and Characterization of Doped Mesoporous TiO2 Materials

Using non-surfacatant organic compounds triethanolamine as the template, TiO2and Fe3+/V5+-TiO2 mesoporous materials were synthesized by solgel and hydrothermal method. The properties of the samples were investigated by XRD, TEM, BET and UV-Vis DRS. The XRD patterns and TEM images confirm that pure TiO2 have the wormhole-like mesoporous structure, which could be preserved by ethanol extraction and destroyed by calcination of template at 450 ℃. However, Fe3+/V5+-TiO2 removed template by calcination has the mesoporous structure, which suggests that the mesoporous structure can be steadied by the doped ion. The appropriate molar fraction of the doped ion is 0.5%. BET studies show that the N2 adsorption|desorption isotherm plots of Fe3+/V5+-TiO2 exhibit type IV isotherms, and specific surface areas about 103.59 and 90.80 m2/g, respectively. The average pore diameter of Fe3+/V5+-TiO2 is about 10.5 and 9.6 nm, respectively. Based on the UV-Vis DRS, the gap adsorption edge in visible light region is revealed for the mesoporous Fe3+/V5+-TiO2, rather than in ultraviolet region of the commercial photocatalyst P25. It is also illuminated that the Fe or V ions are incorporated into the lattice positions of the TiO2 during the preparation.