个人信息Personal Information
副教授
博士生导师
硕士生导师
主要任职:Associate Professor
其他任职:系教工党支部书记
性别:男
毕业院校:大连理工大学
学位:博士
所在单位:化工学院
学科:工业催化. 能源化工
办公地点:大连理工大学西校区化工实验楼B421
电子邮箱:lium@dlut.edu.cn
Role of pentahedrally coordinated titanium in titanium silicalite-1 in propene epoxidation
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论文类型:期刊论文
发表时间:2015-01-01
发表刊物:RSC ADVANCES
收录刊物:SCIE、EI、Scopus
卷号:5
期号:23
页面范围:17897-17904
ISSN号:2046-2069
摘要:Two titanium silicalite-1 samples with different crystal sizes were synthesized in the tetrapropylammonium bromide (TPABr) and tetrapropylammonium hydroxide (TPAOH) hydrothermal systems. The small-crystal TS-1 with a size of 600 nm was then treated with different organic bases. These TS-1 samples were evaluated in the epoxidation of propene, and characterized by ultraviolet-visible diffuse reflectance (UV-vis), X-ray absorption near edge structure (XANES) and Raman spectroscopies. The Ti L-edge absorption spectra show that a new Ti species, pentahedrally coordinated Ti, appears in some of the samples. This pentahedrally coordinated Ti species is correlated with the catalytic oxidation activity of TS-1, closely. Tetrahedrally coordinated Ti in TS-1 is the primary active center for selective oxidation reactions, but the existence of a small amount of pentahedrally coordinated Ti can further improve the catalytic activity. A high molar ratio of Si/Ti (n(Si/Ti)) in the synthesis process (n(Si/Ti) = 92.78) was beneficial for the generation of pentahedrally coordinated Ti. The improved catalytic activity of the TPAOH treated TS-1 is mainly due to the increasing amount of pentahedrally coordinated Ti, besides the elimination of diffusion limitation. Slowing down the crystallization rate can also increase the content of pentahedrally coordinated Ti.