ZSM-5封装Pt-La双金属催化剂的制备及对异丁烷裂解反应的催化性能

Preparation of ZSM-5 Encapsulated Pt-La Bimetallic Catalysts and Their Catalytic Performance for iso-Butane Cracking

采用一步水热法合成了Pt-xLa@HZSM-5催化剂(x为合成体系中La与Pt的摩尔比,x=0.1,0.25,0.5和1.0).利用X射线衍射、扫描电子显微镜、透射电子显微镜、氨气程序升温脱附、吡啶吸附红外光谱和X射线光电子能谱等表征了催化剂的结构、形貌、酸性及金属物种状态等.活性评价结果表明,Pt-0.25La@HZSM-5对异丁烷裂解反应的催化性能最佳,在625℃时,乙烯和丙烯收率为51.1%,而在相同反应条件下,采用浸渍法制备的Pt@HZSM-5-0.25La催化该反应的乙烯和丙烯收率仅为41.4%.

Pt-xLa@HZSM-5 catalysts(x represents the molar ration of La to Pt,x=0.1,0.25,0.5 and 1.0 in the reaction system)were synthesized via one-pot hydrothermal method.The structure,morphology,acidity and metal species state of catalysts were investigated by X-ray diffraction,scanning and transmission electron microscopy,temperature-programmed desorption of ammonia,pyridine-adsorption infrared spectroscopy,and X-ray photoelectron spectroscopy.According to the results of activity test,Pt-0.25La@HZSM-5 had the best catalytic performance for iso-butane cracking,with a yield of 51.1%for ethylene and propylene at 625℃.However,under the same reaction conditions,the yield of ethylene and propylene was only 41.4%on Pt@HZSM-5-0.25La catalyst synthesized by impregnation method for the iso-butane catalytic cracking.