锇嵌入石墨烯催化CO还原N_(2)O反应机理的密度泛函理论研究  

Density functional theory investigation on the mechanism of the reduction of N_(2)O by CO catalyzed by osmium embedded in graphene

作　　者：周健 钟欣欣[1] 张干兵[1] ZHOU Jian;ZHONG Xinxin;ZHANG Ganbing(College of Chemistry and Chemical Engineering,Hubei University,Wuhan 430062,Hubei,China)

机构地区：[1]湖北大学化学化工学院,湖北武汉430062

出　　处：《化学研究》2023年第6期521-526,共6页Chemical Research

基　　金：国家自然科学基金(21675058,21671061)。

摘　　要：N_(2)O和CO都是大气污染物,过渡金属催化CO还原N_(2)O是同时消除它们的有效方法。金属分散于或嵌入石墨烯、氮化碳等二维材料是提高催化性能的有效手段之一。结合相对论赝势,运用UPBE0方法优化了锇单原子嵌入石墨烯催化CO还原N_(2)O循环反应路径上各驻点的几何结构、并计算了热力学函数,进而推测了该催化反应的机理。结果表明该反应存在N_(2)O先吸附(路径a)和CO先吸附(路径b)两种反应历程。路径(a)和路径(b)的表观自由能垒ΔE分别为108.28和135.92 kJ/mol。其中(a)为优势路径,反应可以沿该路径在比较温和的条件下进行。N_(2)O and CO are atmospheric pollutants.Transition metal catalyzed reduction of N_(2)O by CO is an effective method to eliminate and transform them simultaneously.It is one of the effective means to improve catalytic performance with metals dispersing or embedding in two-dimensional materials such as graphene and carbon nitride.Combining relativistic pseudopotential and density functional theory(DFT)method,the geometry of each stationary point on the catalytic cycle of the reaction pathway for the reduction of N_(2)O by CO catalyzed by osmium single atom embedded in graphene was optimized by UPBE0 method,and the thermodynamic function was calculated.Then the mechanism of the reaction was speculated.The results show that there are two reaction processes:N_(2)O adsorption first(channel a)and CO adsorption first(channel b).The apparent free energy barriersΔE of the two channels are 108.28 and 135.92 kJ/mol,respectively,where(a)is the preferred pathway,the reaction may occur along the pathway(a)under mild conditions.

关 键 词：密度泛函理论 CO还原N_(2)O 锇嵌入石墨烯 催化转换频率 

分 类 号：O643[理学—物理化学]