气相金属催化反应综述（英文）

发布时间：2018-04-20 16:11

本文选题：金属催化 + 团簇　；参考：《催化学报》2017年09期

【摘要】：金属催化剂在工业、环境、能源以及生物等过程具有重要的应用.设计具有特定活性、环境友好型以及室温下具有反应活性的催化剂,需要在分子水平对金属催化剂的基元步骤,活性位点的结构以及催化反应微观机理有充分的认识.然而,由于宏观催化剂表面结构异常复杂,催化反应常受到溶剂、压力、金属颗粒团聚、催化剂表面缺陷等因素的干扰,利用现有实验仪器,从微观角度探索金属催化反应机理仍具有较大挑战,因此,对金属催化剂活性位的结构以及反应微观机理的认识还不十分清楚.质谱方法结合现代量子化学理论计算,提供了在气相条件下实验探索化学反应微观机理的有力工具,团簇反应可在隔离外界条件、可控以及可重复条件下进行,可以排除一些难以控制因素的干扰,可在化学键和分子结构水平认识金属活性位的结构以及催化反应的微观机理.气相金属团簇离子可用多种实验方法制备,与反应物分子反应后可利用多种质谱仪器探测,根据实验上所得的具有反应活性的团簇,结合现代量子化学理论模拟,得到金属催化反应的基元步骤以及微观反应机理信息,所得反应机理信息为宏观催化剂的设计提供重要理论研究基础.本综述总结了团簇实验上已经探测到的金属单原子离子、金属团簇、金属氧化物团簇和金属化合物催化的气相反应.反应物分子囊括了大量的无机和有机分子,包括CO,H_2,CH_4,C_2H_2,C_2H_4,C_6H_6,CH_3OH,HCOOH,CH_3COOH等.本综述主要介绍了以下三类催化反应:(1)CO催化氧化;(2)CH4催化转化;(3)催化脱羧反应,并重点关注贵金属单原子掺杂团簇独特的催化反应性.单原子催化剂可最大限度地利用有限的贵金属.在化学反应方面,单原子催化剂具有特异的反应活性,选择性以及稳定性.本综述对气相团簇反应中报道的两个重要的贵金属单原子掺杂团簇的催化反应进行了详细介绍:(1)金原子掺杂的Au Al_3O_(3-5)~+团簇为首次报道的可以利用分子氧催化氧化CO的团簇单原子催化剂,我们对Au原子起催化作用的本质原因进行了介绍:(2)铂原子掺杂的Pt Al_3O_(5-7)~-团簇能利用分子氧催化氧化CO,该研究提出了"电负性阶梯"效应来解释Pt原子催化的微观机理,且此效应有望对大部分贵金属适用.此外,本综述对CO催化氧化反应和CH_4催化转化反应的研究现状以及尚未解决的问题进行了剖析.相比CO的催化氧化反应,科学家对CH4催化转化反应机理的认识还不够深入,还需要进一步实验研究,而团簇单原子催化剂有望在此领域有所突破.
[Abstract]:Metal catalysts have important applications in industrial, environmental, energy and biological processes. The design of catalysts with specific activity, environmental friendliness and reaction activity at room temperature requires a full understanding of the basic steps of metal catalysts, the structure of active sites and the microscopic mechanism of catalytic reactions at the molecular level. However, because the surface structure of macroscopic catalyst is very complicated, the catalytic reaction is often interfered by solvent, pressure, metal particle agglomeration, catalyst surface defect and so on. It is still a challenge to explore the mechanism of metal catalytic reaction from the micro point of view. Therefore, the structure of the active site of metal catalyst and the micro mechanism of the reaction are not well understood. The mass spectrometry method combined with the modern quantum chemistry theory provides a powerful tool for the experimental exploration of the microscopic mechanism of chemical reactions in the gas phase. Cluster reactions can be carried out under isolated, controllable and repeatable conditions. The interference of some uncontrollable factors can be eliminated and the structure of active sites of metals and the microscopic mechanism of catalytic reactions can be recognized at the level of chemical bond and molecular structure. Gas phase metal cluster ions can be prepared by a variety of experimental methods. After reacting with reactants, they can be detected by various mass spectrometry instruments. According to the experimental results of clusters with reactive activity and modern quantum chemistry theory simulation, The basic steps and microcosmic reaction mechanism information of metal-catalyzed reaction were obtained. The obtained reaction mechanism information provided an important theoretical basis for the design of macroscopic catalysts. This review summarizes the gas phase reactions catalyzed by metal monatomic ions, metal clusters, metal oxide clusters and metal compounds, which have been detected in cluster experiments. The reactants contain a large number of inorganic and organic molecules, including the COHSP 2CH4S / C2H2S / C2H2S / C2H4 / C6H6 / CH3HCOOH- CH3COOH. In this review, the following three kinds of catalytic reactions: 1: 1 ~ (1) CO catalytic oxidation of C ~ (2 +) H _ (2) H _ (4) and ~ (3)) catalytic decarboxylation are introduced, with emphasis on the unique catalytic reactivity of noble metal monatomic doped clusters. Monatomic catalysts can maximize the use of limited precious metals. In chemical reaction, monatomic catalyst has specific activity, selectivity and stability. In this paper, the catalytic reactions of two important noble metal monoatomic doped clusters reported in the gas phase cluster reaction are introduced in detail. Cluster monatomic catalyst, We have introduced the essential reason for the catalytic action of au atoms. (2) Platinum doped Pt Al3O / 5 / 7C clusters can use molecular oxygen to catalyze the oxidation of CO.In this study, the electronegativity ladder effect is proposed to explain the microscopic mechanism of Pt atom catalysis. This effect is expected to be applicable to most precious metals. In addition, the research status and unsolved problems of CO catalytic oxidation and CH_4 catalytic conversion were analyzed. Compared with the catalytic oxidation of CO, the mechanism of catalytic conversion of CH4 is not well understood by scientists, and further experimental research is needed, and the cluster monatomic catalyst is expected to make a breakthrough in this field.
【作者单位】：中国科学院化学研究所动态与稳态结构实验室;华南理工大学化学与化工学院;
【基金】：supported by the National Natural Science Foundation of China(21303215,21325215,21573246) the Major Research Plan of China(No.2013CB834603) the grant from the Youth Innovation Promotion Association,Chinese Academy of Sciences(2016030)~~
【分类号】：O643.32

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