Study on the Sol-gel Process of TEOS by React-IR
(0) Porous silica was prepared through TEOS sol-gel process catalyzed by acid-base joint catalyst, and the process was monitored by React IR?. Based on the measurements, mechanism of TEOS hydrolyzation and succedent condensation polymerization was inferred. Under acidic conditions, H+ attacks -OR group of TEOS firstly, then the electronegative Cl- can attack Si(4+) and make TEOS be hydrolyzed. When basic catalyst was added, the reaction will be accelerated. The promotion effect of base is attributed to the direct nucleophilic reaction mechanism and the smaller size of OH, which can attack Si more easily. Thirdly, silanol, generated from TEOS hydrolyzation, attract Si-OR or other Si-OH around; thereby resulting rapid dehydration or de-alcohol reaction. So the condensation polymerization rate is elevated, and Si-O-Si bond comes into being. Lastly, cross-linking reaction among Si-O-Si bonds forms the particle like conglomeration. The porous silica was characterized by SEM and N2 adsorption-desorption technique. It was shown that the silica had large specific surface area, 818.5 m2/g, and relatively narrow distribution of pore size in meso-scale. Futhermore, the mesopores were nonuniform in shape and arrangement.
TEOS Sol-gel Catalyst React-IR Reaction mechnaism
Huahua Zhou Wei Xue Fang Li Yanfei Qin
Key Laboratory of Green Chemical Technology and High Efficient Energy Saving of Hebei Province Hebei University of Technology Tianjin 300130, China
国际会议
2010 International Conference on Nano Science and Technology(2010年IEEE纳米科技国际会议 ICNST2010)
成都
英文
288-291
2010-12-17（万方平台首次上网日期，不代表论文的发表时间）