不断增加的二氧化碳排放量，对生态系统造成了严重威胁，二氧化碳主要来源于煤和石油燃烧。甲烷是页岩气和天然气的主要成分，是生产液体燃料和高价值化学品的重要原料，但也是一种温室气体，甲烷的温室效应约为二氧化碳的25倍。甲烷二氧化碳重整技术因将甲烷和二氧化碳同时转化为合成气CO和H2而备受关注，但反应过程中会导致催化剂的烧结和聚集，设计制备抗积碳、抗烧结性能优越的催化剂是甲烷二氧化碳重整反应亟待解决的关键问题。从限域角度出发，设计性能优异的催化剂并应用于化学反应备受关注。介绍了多种限域型高性能甲烷二氧化碳重整催化剂的研究现状，分别为孔道限域催化剂、核壳限域催化剂、晶格限域催化剂、表面空间限域催化剂和多重限域催化剂，并对其应用于甲烷二氧化碳重整反应的性能进行了阐述，最后对限域策略应用于高性能重整催化剂开发的未来发展方向进行了展望。孔道限域影响反应物种和活性中心的可接近性、催化剂的活性表面积以及结构的稳定性；核壳限域使反应物与活性中心接触更好，增强了与活性中心的相互作用；晶格限域可以有效将贵金属或非贵金属锚定在排列规律的空间骨架上，提高活性中心的分散度；表面空间限域催化剂具有高比表面积，高度有序的孔结构和窄孔径分布（在纳米范围内）的中孔载体可以提供大量的催化活性位点并稳定金属纳米颗粒；多重限域可以将活性中心限域在催化剂中，降低其暴露程度，提高催化剂的抗积碳能力。限域型催化剂被广泛应用于催化剂的设计制备过程，限域为催化反应体系提供了一个（物理或化学）约束环境，这为未来理性设计高热稳定催化剂提供了思路。未来有望通过限域效应（特别是表面空间限域和多重限域策略）来调控设计催化剂应用于高温高压甲烷二氧化碳重整反应，进一步深入探究催化剂应用于二氧化碳重整反应机理（二氧化碳如何为甲烷提供活泼氧），为甲烷二氧化碳重整反应的工业应用提供新的催化剂。

With the continuous increase of carbon dioxide emissions,mainly from the burning of coal and oil,the ecosystem is seriously threatened. Methane is a major component of shale gas and natural gas,and is an important feedstock for producing liquid fuels and high-value chemicals. But it is also a greenhouse gas,and the greenhouse effect of methane is 25 times that of carbon dioxide. The methane-carbon dioxide reforming technology has attracted much attention because of its simultaneous conversion of methane and carbon dioxide into syngas CO and H2. However,the sintering and aggregation of catalysts will occur during the reaction process,so the design and preparation of catalysts with excellent resistance to carbon accumulation and sintering is the key problem to be solved urgently in methane carbon dioxide reforming reaction. From the point of view of limited domain,the design of catalysts with excellent performance and their application in chemical reactions widely concerned.In this review,the research status of several kinds of confined high performance methane carbon dioxide reforming catalysts were introduced,including pore confined catalysts,core-shell confined catalysts,lattice confined catalysts,surface space confined catalysts and multiple confined catalysts.In addition,the performance of its application in reforming methane with carbon dioxide was described.Finally,the future development direction of application of confined strategy in the development of high-performance reforming catalysts was prospected. The pore-channel confinement affects the accessibility of reaction species and active center,active surface area and structural stability of the catalyst. The core-shell confinement can effectively promote the contact between the reactants and the active center and enhance the interaction with the active center. The lattice limits can effectively anchor precious metals or non-precious metals to the spatial framework of regular arrangement and improve the dispersion of active centers. Surface space confined catalysts with high specific surface area,highly ordered pore structure and mesoporous carriers with narrow pore size distribution (in the nanometer range) can provide a large number of catalytic active sites and stabilize metal nanoparticles. The multiple confinement can well limit the active center in the catalyst,reduce its exposure and improve the anti-carbon accumulation ability of the catalyst. Confined catalysts are widely used in the design and preparation of catalysts. Confined catalysts provide a constrained environment (physical or chemical) for the catalytic reaction system,which provides an idea for rational design of high thermal stability catalysts in the future.In the future,it is expected to pass the confined effect (especially surface space confinement and multiple confinement strategy) to regulate the design catalyst used in high temperature and high pressure carbon dioxide reforming of methane,and further explore the catalyst used in carbon dioxide reforming reaction mechanism (carbon dioxide is how to provide active oxygen for methane),which provides a new catalyst for the industrial application of methane carbon dioxide reforming reaction.

0 引言

1 甲烷二氧化碳重整反应

2 限域型催化剂

   2.1 孔道限域

   2.2 核壳限域

   2.3 晶格限域

   2.4 表面空间限域

   2.5 多重限域

3 结语与展望