表面接枝法合成Si掺杂介孔SO_4^(2-)/TiO_2  

Synthesis of Silicon-Doped Mesoporous SO_4^(2-)/TiO_2 by Surface Joint Method

作　　者：陈垚翰[1] 李国亮[1] 张昭[1] 

机构地区：[1]四川大学化工学院,四川成都610065

出　　处：《化学反应工程与工艺》2008年第6期481-487,共7页Chemical Reaction Engineering and Technology

基　　金：国家自然科学基金(50474071)

摘　　要：以工业硫酸钛液水解得到的介孔偏钛酸为载体,正硅酸乙酯(TEOS)为浸渍剂,采用表面接枝法制备了 Si 掺杂的介孔 SO_4^(2-)/TiO_2。通过 X 射线衍射(XRD)、N_2吸附-脱附、X 射线光电子能谱(XPS)和傅立叶-红外光谱(FT-IR)对焙烧产物进行表征,考察了超声波和微波外场对浸渍过程的影响以及 Si提高介孔 TiO_2热稳定性的机制。结果表明,掺杂 Si 形成的 Ti-O-Si 键对介孔 TiO_2的孔结构起到支持作用,阻止晶粒长大和提高锐钛矿向金红石矿的相变温度,使 SO_4^(2-)稳定的介孔 TiO_2的热稳定性提高,在700℃焙烧后仍保持138 m^2/g 的比表面积;超声波和微波场强化了浸渍过程,大大缩短了浸渍时间,促进 Si 在内外表面的分布。The silicon-doped mesoporous SO4^2-/TiO2 was prepared by surface joint method using mesoporous metatitanic acid from hydrolysis of industrial titanyl sulfate solution as a support and tetraethylorthosilicate as an impregnating reagent. The calcined products were characterized using X-ray diffraction （XRD）, N2 adsorption-desorption, X-ray photoelectron spectroscopy （XPS）and infrared spectroscopy （IR）. The influence of ultrasonic and microwave outfield on impregnating process was investigated and mechanism of doping Si to improve the thermal stability of SO4^2-/TiO2 was discussed. The results showed that the formed Ti-O-Si bond supported the pore structure, the presence of Si atom in the framework of TiO2 prevented crystallite growth and phase transformation from anatase to rutile, as a result, the thermal stability of Si-doped mesoporous SO4^2-/TiO2 was higher than mesoporous SO4^2-/TiO2, the sample calcined at 700 ℃ for 2 h had a surface area of 138 m^2/g. Ultrasonic and microwave irradiation strengthened dipping, shortened dipping time and promoted the doped Si distribution or the outer and internal surface of mesoporous SO4^2-/TiO2.

关 键 词：介孔二氧化钛 硅掺杂 浸渍 外场作用 热稳定性 

分 类 号：TQ426.65[化学工程]