摘要
Non-oxidative ethane dehydrogenation is a promising route to produce ethene.Herein,PtSn supported catalysts were investigated to achieve better ethane dehydrogenation performance by introduction of different Zr promoters,i.e.,framework Zr and ZrO_(2),to mesoporous MCM-41.In-situ XRD,TEM and CO chemisorption show that aggregation of metal particles and phase segregation of Pt_(3)Sn to Pt and PtSn_(3) at high temperature occur for PtSn/M,leading to bad ethane dehydrogenation activity.Strong interaction be-tween ZrO_(2) and PtSn species,as proved by XPS,results in restrained metal particles,which promotes the initial reactivity.However,Pt phase generated on surface is disadvantageous for the desorption of produced ethene as indicated by CO-IR and C_(3)H_(6)-TPD,and pyridine-IR and NH_(3)-TPD indicate strong acidity generated.Both deactivate the catalyst rapidly by deep dehydrogenation and coking.Moderate interaction between PtSn species and Si-O-Zr with much weaker acidity is formed when framework Zr is incorporated into MCM-41,which benefits the dispersion of metal particles,formation of Pt_(3)Sn/Pt species and stabilization of metal species from phase segregation.Outstanding initial ethane conversion and ethene selectivity of ca.99%were achieved for the optimal PtSn/ZrM,which is more coking-tolerant and stable by generating graphitic carbon mainly on support instead of active metals.
基金
support of the National NaturalScience Foundationof China(No.22121004)。
作者简介
Chengxiang Shi,E-mail:cxshi@tju.edu.cn;Ji-Jun Zou,jj_zou@tju.edu.cn。
