Pt基催化剂上CO2辅助丙烷脱氢的反应机理
Reaction Mechanism of CO2-Assisted Dehydrogenation of Propane Over Pt-Based Catalysts
杨倩 1聂小娃 1丁凡舒 1郭新闻1
作者信息
- 1. 大连理工大学化工学院精细化工国家重点实验室PSU-DUT联合能源研究中心智能材料化工前沿科学中心,辽宁大连 116024
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摘要
Pt基双金属是一种具有发展前景的丙烷脱氢催化剂,CO2在Pt基催化剂上辅助丙烷脱氢的微观反应机理与优势能量路径尚不明确,为此,采用密度泛函理论(DFT)计算研究了 Pt(111)表面及Pt3Mn(111)表面上丙烷直接脱氢反应(PDH)及CO2辅助丙烷脱氢反应(CO2-ODH)的反应网络与关键步骤.计算结果表明:CO2的加入可以降低PDH速控步骤的能垒,对于消耗表面H有利,促进了丙烷脱氢反应正向移动,有利于生成丙烯,从而改变了反应路径和反应动力学;CO2在消除积炭反应中的能垒较高,但是Mn的引入有利于CO2消除积炭.此外,第二金属组分Mn的引入,不但有利于产物丙烯脱附,还提高了 C—C裂解能垒,从而提高了丙烯的选择性.
Abstract
Pt-based bimetals are promising catalysts for propane dehydrogenation.The microscopic reaction mechanism and dominant energy pathway of CO2-assisted propane dehydrogenation on Pt-based catalyst are still unclear.Therefore,the density functional theory(DFT)was used to study the reaction networks and key steps of direct dehydrogenation of propane(PDH)and CO2-assisted propane dehydrogenation(CO2-ODH)on Pt(111)and Pt3Mn(111)surfaces.The calculation results show that the addition of CO2 can reduce the energy barrier of rate-limiting step of PDH,which is beneficial to the consumption of surface H species,thus promoting the forward reaction of propane dehydrogenation.This is conducive to the formation of propylene,and further changes the reaction pathway and reaction kinetics.The energy barrier of CO2 in elimination of carbon deposition is high,and the introduction of Mn is conducive to the elimination of carbon deposition by CO2.In addition,the introduction of the second metal component Mn not only reduces the desorption energy of propylene product,but also increases its C—C cracking barrier,thus improving the selectivity to propylene product.
关键词
丙烷脱氢/二氧化碳/辅助/Pt基催化剂/密度泛函理论/反应机理Key words
propane dehydrogenation/carbon dioxide/assistance/Pt-based catalyst/density functional theory/reaction mechanism引用本文复制引用
基金项目
辽宁省自然科学基金面上项目(2023-MS-105)
出版年
2024
NETL
NSTL
万方数据