Pt/HZSM-5基催化剂双功能协同性对正丁烷催化裂解反应机制的影响

轻质烷烃结构稳定,化工利用率低.催化裂解轻质烷烃是其高值利用的重要途径,相关研究同时对C-C键和C-H键活化和演变调控具有重要意义.本文在基于原子层沉积法构建高稳定Pt/HZSM-5基双功能模型催化剂的基础上,研究了不同酸性HZSM-5分子筛引入脱氢组分Pt对反应路径及目的产物低碳烯烃的影响规律.研究发现,双功能催化剂...

The effect of bifunctionality synergy of Pt/HZSM-5 based catalyst on reaction mechanism of n-butane catalytic cracking

Light alkanes are stable,and they are not fully utilized in chemical industry.Catalytic cracking is an important process for the valorization of light alkanes,and the related study is also of significant importance for the activation and evolution regulation of C?H bond and C?C bond.In this work,on the basis of highly stable Pt/HZSM-5based bifunctional model catalysts constructed by atomic layer deposition,the dehydrogenation component Pt was introduced onto HZSM-5 zeolites with different acidic properties,and their influences on the reaction pathways and formation of targeted light olefins were studied.It was found that the dehydrogenation function of Pt and cracking role of acidic HZSM-5 zeolites work in synergy.Among the catalysts with the introducing of Pt onto HZSM-5 zeolites with different SiO₂/Al₂O₃ratios,the dehydrogenation effect brought by metal introduction onto zeolite with high SiO₂/Al₂O₃ratio is stronger than those introduced onto the ones with low SiO₂/Al₂O₃ratios.Meanwhile,the introducing of dehydrogenation component onto acidic supports with different cracking abilities would also vary the formation pathways of light olefins.Specifically,with introducing Pt,the pathway of butene formation is enhanced on zeolite with high SiO₂/Al₂O₃ratio,while the pathways of ethene and propene formation are strengthened on zeolites with low ones.With further decreasing SiO₂/Al₂O₃ratio,the pathway of ethene formation is mainly enhanced.The present study is expected to provide guidance for the regulation of reaction pathways and future design of efficient bifunctional catalysts for complex heterogeneous reactions.