钌基催化剂催化的气固相反应（英文）
发布时间：2018-12-23 11:02
【摘要】：催化剂被广泛应用于各种化学品的生产,从原子尺度了解整个催化反应体系有利于合理设计新型催化剂.参与气固相反应的催化剂主要有贵金属催化剂和过渡金属催化剂.近年来,Ru基催化剂由于在低温低压下表现出良好的催化活性而广泛应用于一些气固相反应.本文对Ru的基本性质、氧化行为以及Ru基催化剂的理论研究进行综述.介绍了钌基催化剂参与的气固相反应,包括挥发性有机物的催化氧化、一氧化碳优先氧化(PROX)、氨合成、氯化氢氧化以及甲烷部分氧化,分析了催化性能与理化性质之间的构效关系,提出了钌基催化剂在相关反应中存在的问题以及未来发展趋势.Ru具有多种氧化态,在Ru基催化剂参与的气固相反应中,金属Ru和/或RuO_2被认为是活性物种,通常反应温度在400oC以下.Ru(0001)晶面在O_2存在条件下,随着氧气含量的不同会从中间态过渡到氧化态,实验证明该晶面属于RuO_2.理论研究证实了在反应过程中RuO_2的存在,并提出了核壳结构,对于其它气固相反应的机理研究有一定启发.挥发性有机物(VOC)的催化氧化主要集中烷烃、烯烃、芳烃以及卤代烃的催化氧化,催化剂的理化性质包括颗粒粒径、价态和晶体结构等对催化活性有很大影响,并且Ru基催化剂对卤代烃的催化氧化表现出良好的抗卤性,同时多卤代副产物低于其它贵金属体系.Ru基催化剂在低温条件下对PROX具有高的活性和选择性,并且可以有效抑制H_2氧化、CO甲烷化和CO_2甲烷化等副反应发生.氨合成的难点在于N≡N具有很强的解离能,许多研究表明,氨合成使用的Ru基催化剂的催化性能与载体性质密切相关,Ru与载体之间强的相互作用使得电子可以迅速地从载体转移到Ru颗粒上,掺杂其它有效元素可能会提供更多的氧空位和有效防止高温焙烧导致催化剂烧结.对于HCl氧化虽然研究较少,但是Over等人对HCl氧化机理进行了深入研究,并且日本住友化工设计的Ru基催化剂已经商业化.Ru基催化剂可以有效降低甲烷部分氧化的反应温度和压力,并具有高的选择性和稳定性,避免副产物生成.现有催化系统以及新型催化剂开发仍面临诸多挑战,例如:对于单一VOC氧化过程和多元VOCs催化氧化的机理和动力学需要进一步研究;对于氨合成需要寻求具有高电导率的载体,从而将电子快速转移到Ru颗粒表面,使得氨合成在更低温度下进行;为了避免副产物生成,需确保新型Ru基催化剂上PROX和甲烷部分氧化在低温低压条件下进行;Ru基催化剂理化性质对活性的影响以及失活等问题需要进一步研究.
[Abstract]:Catalysts are widely used in the production of various chemicals. Understanding the whole catalytic reaction system at atomic scale is beneficial to the rational design of new catalysts. The catalysts involved in the gas-solid reaction are mainly noble metal catalyst and transition metal catalyst. In recent years, Ru catalysts have been widely used in some gas-solid reactions due to their good catalytic activity at low temperature and low pressure. In this paper, the basic properties, oxidation behavior and theoretical study of Ru based catalysts are reviewed. The gas-solid reactions of ruthenium based catalysts, including catalytic oxidation of volatile organic compounds, (PROX), ammonia synthesis, hydrogen chloride oxidation and partial oxidation of methane, were introduced. The structure-activity relationship between catalytic performance and physicochemical properties was analyzed, and the problems and future trends of ruthenium based catalysts in the related reactions were put forward. Ru has a variety of oxidation states and is involved in the gas-solid reactions of Ru based catalysts. Metal Ru and / or RuO_2 are considered to be active species, usually at the reaction temperature below 400oC (. Ru (0001) in the presence of O _ 2, the transition from intermediate state to oxidized state varies with the oxygen content. The experimental results show that the crystal plane belongs to RuO_2.. The existence of RuO_2 in the reaction process was confirmed by theoretical study, and the core-shell structure was proposed, which has some implications for the study of the mechanism of other gas-solid reactions. The catalytic oxidation of volatile organic compounds (VOC) is mainly concentrated on alkanes, alkenes, aromatics and halogenated hydrocarbons. The physicochemical properties of the catalysts, including particle size, valence state and crystal structure, have great influence on the catalytic activity. Moreover, Ru based catalysts exhibited good halogen-resistance to halogenated hydrocarbons, and polyhalogenated by-products were lower than other noble metal systems. Ru based catalysts had high activity and selectivity to PROX at low temperature. And the side reactions such as H _ 2 oxidation, CO methanation and CO_2 methanation can be effectively inhibited. The difficulty of ammonia synthesis lies in the strong dissociation energy of N 鈮，
本文编号：2389898
[Abstract]:Catalysts are widely used in the production of various chemicals. Understanding the whole catalytic reaction system at atomic scale is beneficial to the rational design of new catalysts. The catalysts involved in the gas-solid reaction are mainly noble metal catalyst and transition metal catalyst. In recent years, Ru catalysts have been widely used in some gas-solid reactions due to their good catalytic activity at low temperature and low pressure. In this paper, the basic properties, oxidation behavior and theoretical study of Ru based catalysts are reviewed. The gas-solid reactions of ruthenium based catalysts, including catalytic oxidation of volatile organic compounds, (PROX), ammonia synthesis, hydrogen chloride oxidation and partial oxidation of methane, were introduced. The structure-activity relationship between catalytic performance and physicochemical properties was analyzed, and the problems and future trends of ruthenium based catalysts in the related reactions were put forward. Ru has a variety of oxidation states and is involved in the gas-solid reactions of Ru based catalysts. Metal Ru and / or RuO_2 are considered to be active species, usually at the reaction temperature below 400oC (. Ru (0001) in the presence of O _ 2, the transition from intermediate state to oxidized state varies with the oxygen content. The experimental results show that the crystal plane belongs to RuO_2.. The existence of RuO_2 in the reaction process was confirmed by theoretical study, and the core-shell structure was proposed, which has some implications for the study of the mechanism of other gas-solid reactions. The catalytic oxidation of volatile organic compounds (VOC) is mainly concentrated on alkanes, alkenes, aromatics and halogenated hydrocarbons. The physicochemical properties of the catalysts, including particle size, valence state and crystal structure, have great influence on the catalytic activity. Moreover, Ru based catalysts exhibited good halogen-resistance to halogenated hydrocarbons, and polyhalogenated by-products were lower than other noble metal systems. Ru based catalysts had high activity and selectivity to PROX at low temperature. And the side reactions such as H _ 2 oxidation, CO methanation and CO_2 methanation can be effectively inhibited. The difficulty of ammonia synthesis lies in the strong dissociation energy of N 鈮，
本文编号：2389898
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