Zn-Pt/ZSM-5催化CO_(2)辅助丙烷脱氢的密度泛函理论研究  

A Density Functional Study of CO_(2)-Assisted Propane Dehydrogenation Catalyzedby Zn-Pt/ZSM-5

作　　者：屈姝良 樊华华 聂小娃[1] 丁凡舒[1] 郭新闻[1] QU Shuliang;FAN Huahua;NIE Xiaowa;DING Fanshu;GUO Xinwen(Frontier Science Center for Smart Materials,State Key Laboratory of Fine Chemicals,School of Chemical Engineering,Dalian University of Technology,Dalian 116024,China)

机构地区：[1]大连理工大学化工学院精细化工国家重点实验室智能材料化工前沿科学中心,辽宁大连116024

出　　处：《石油学报（石油加工）》2024年第2期392-403,共12页Acta Petrolei Sinica(Petroleum Processing Section)

基　　金：中央高校基本科研业务费(DUT21LK22,DUT22LAB602)资金资助。

摘　　要：通过密度泛函理论(DFT)计算研究了Zn-Pt/ZSM-5催化丙烷脱氢的反应机理,筛选出最优能量途径。研究发现丙烷在Zn-Lewis和Pt-Lewis酸位点上具有不同的反应路径和限速步骤。Bader电荷计算结果表明,丙烷分子吸附后,[Zn-O-Pt]^(2+)活性位点中Pt上的电子密度增加,有利于丙烷活化,Pt位点对H的吸引能力更强,导致Pt—H键断裂生成H_(2)需要克服较高能垒。Pt的引入改变了Zn/ZSM-5的电子性质,影响其催化剂性能。在反应体系中引入CO_(2)改变了丙烷脱氢反应路径,降低了限速步骤能垒,促进反应正向进行。In this work,the reaction mechanism of propane dehydrogenation to propene over Zn-Pt/ZSM-5 catalyst was studied by density functional theory(DFT)calculations and the optimal energy pathway was clarified.It has been found that propane conversion has different reaction paths and rate-limiting steps on the Zn-Lewis and Pt-Lewis acid sites of Zn-Pt/ZSM-5.Bader charge calculation results show that the adsorption of propane can increase the charge density on the Pt site,thus facilitating the propane activation and strengthening the Pt—H bond.As a result,the Pt—H bond cleavage to form H_(2) has to overcome a high barrier on the Pt site.The introduction of Pt has modified the electronic properties of Zn/ZSM-5,and thus affected its catalytic performance.In the presence of CO_(2),the propane dehydrogenation pathway was altered and the energy barrier of rate-limiting step was reduced,thus promoting the propane conversion to propene.

关 键 词：丙烷脱氢 Zn-Pt/ZSM-5 CO_(2)辅助 反应机理 密度泛函理论 

分 类 号：O643.12[理学—物理化学]