摘要
【目的】乙烯中微量乙炔半加氢存在的主要问题是过度加氢。高浓度的乙烯是导致过度加氢的主要原因,因此,设计具备乙炔富集能力的催化剂对于乙炔半加氢反应具有重要意义。【方法】设计了具有乙炔富集能力的模型催化剂——[MB_(12)H_(x)]^(2-)(M=Pd、Ni、Ag;x=9、10),基于密度泛函理论(DFT)系统研究了乙烯和乙炔在催化剂表面的吸附行为,及其催化乙炔选择性加氢的反应机理。乙炔加氢反应涉及的各物种(C_(2)H_(2)、C_(2)H_(3)、CHCH_(3)、C_(2)H_(4)、C_(2)H_(5)、H_(2)以及H原子)在催化剂表面的吸附能、反应热和活化能进行了详细计算。【结果】计算结果表明,在[PdB_(12)H_(9)]^(2-)、[NiB_(12)H_(9)]^(2-)、[AgB_(12)H_(10)]^(2-)上,过度加氢(C_(2)H_(4)+H=C_(2)H_(5))的能垒明显高于半氢化反应(C_(2)H_(4)脱附)的能垒,其中[PdB_(12)H_(9)]^(2-)表现出了最好的乙烯选择性(2.02 eV),同时[PdB_(12)H_(9)]^(2-)较低的限速步骤活化能垒体现出该催化剂具备较高的反应活性(1.18 eV)。
【Purposes】The main problem of semi-hydrogenation of trace acetylene in ethylene is excessive hydrogenation.High concentration of ethylene is the main cause of excessive hydrogenation,so it is important to design a catalyst with acetylene enrichment ability for semi-hydrogenation of acetylene.【Methods】A model catalyst with acetylene enrichment capability,[MB_(12)H_(x)]^(2-)(M=Pd,Ni,Ag;x=9,10),based on density functional theory was designed,the adsorption behavior of ethylene and acetylene on its surface and the reaction mechanism of selective hydrogenation of acetylene were systematically studied.The adsorption energy,reaction heat,and activation energy of each species involved in acetylene hydrogenation reaction(C_(2)H_(2),C_(2)H_(3),CHCH_(3),C_(2)H_(4),C_(2)H_(5),H_(2),and H atoms)on the catalyst surface were calculated in detail.【Results】The calculation results show that the energy barriers of excessive hydrogenation(C_(2)H_(4)+H=C_(2)H_(5))at[PdB_(12)H_(9)]^(2-),[NiB_(12)H_(9)]^(2-),and[AgB_(12)H_(10)]^(2-)are significantly higher than that of semi-hydrogenation(C_(2)H_(4) desorption).Among them,[PdB_(12)H_(9)]^(2-)shows the best ethylene selectivity(2.02 eV),and[PdB_(12)H_(9)]^(2-)shows a high reactivity(1.18 eV)with a lower rate-limiting step activation energy barrier.
作者
陈康杰
王婉楠
史秀锋
任瑞鹏
吕永康
CHEN Kangjie;WANG Wannan;SHI Xiufeng;REN Ruipeng;LYU Yongkang(State Key Laboratory for Clean and Efficient Utilization of Coal Energy Jointly Established by the Ministry of Science and Technology and Shanxi Province,Taiyuan University of Technology,Taiyuan,Shanxi,China;Shanxi-Zheda Institute of Advanced Materials and Chemical Engineering,Taiyuan,Shanxi,China;College of Chemistry,Taiyuan University of Technology,Taiyuan,Shanxi,China)
出处
《太原理工大学学报》
北大核心
2025年第4期639-647,共9页
Journal of Taiyuan University of Technology
基金
国家自然科学基金资助项目(22178244)
山西省自然科学基金(20210302123118)
山西浙大新材料与化工研究院项目(2021SX-FR001)
吕梁市校地合作重点研发专项(2022XDHZ07)。
作者简介
第一作者:陈康杰,硕士研究生,(E-mail)chenkj0610@163.com;通信作者:任瑞鹏,博士,教授,主要从事多相催化研究,(E-mail)renruipeng@tyut.edu.cn.
