双掺杂介孔催化剂Fe-Ti-MCM-41的制备及催化性能

Preparation and Catalytic Properties of Fe-Ti-MCM-41

通过对负载型Ti-MCM-41催化材料进行铁离子掺杂,制备了双掺杂介孔催化剂Fe-Ti-MCM-41.采用XRD,FTIR,HRTEM,BET和ICP等方法对材料的组成和结构进行了表征,并研究了金属铁离子掺杂量和后处理温度等对介孔钛硅催化材料氧化催化性能的影响.当掺杂量较低时,铁离子主要是通过化学键键合在分子筛上,呈分子级分散,得到的催化剂对环辛烯、环己烯、苯乙烯和2-甲基苯乙烯等底物都表现出较好的催化活性.当掺杂量较高时,金属易形成聚集态,导致催化剂比表面积下降,使催化活性降低.

Fe incorporated Ti-MCM-41 catalysts were prepared by incipient wetness impregnation method.The samples were characterized by X-ray diffraction（XRD）,Fourier transform infrared spectroscopy（FTIR）,high resolution transmission electron microscopy（HRTEM）,nitrogen adsorption-desorption isotherms and inductively coupled plasma atomic emission spectrometry（ICP）.The effects of doping amounts of Fe and calcination temperature on the catalytic performance of the catalyst were investigated.Catalytic activity tests were conducted in the epoxidation of cis-cyclooctene with aqueous H2O2 as an oxidant.It is found that incorporation of low amount of ferric into the mesoporous material favors to obtain Fe-Ti-MCM-41 catalyst with high catalytic activity.The enhanced catalytic activity may be attributed to that the majority of Fe3＋ are highly dispersed by single molecule,which brings up efficient excitation of Ti active sites.More loading amount of Fe3＋ leaded to the cluster,so the conversion and selectivity of cyclooctene epoxide decreased.