Abstract:

Metal-based catalysts suffer from sintering of metal particles at high temperature, which causes the decline of catalytic performance and even deactivation. Therefore, improving the thermal stability of metal-based catalysts becomes a critical challenge for heterogeneous catalysis. In this review, the two main sintering mechanisms for metal-based catalyst has elaborated, including particle migration and Ostwald ripening. Four approaches to determine the sintering mechanism by particle size distribution, particle growth kinetics, in situ transmission electron microscopy analysis, and experimental and computational prediction were established. Among them, temperature affects the kinetic energy of metal particle, which is the main physical factor for particle sintering, while chemical potential, as one of the chemical factors for particle sintering, is greatly affected by the metal-support interaction. In addition, we summarized the research progress in developing the sintering-resistant catalysts on the basis of metal-support interaction, spatial confinement and other novel structure strategies. Furthermore, the development and goal for the research and construction of sintering-resistant catalysts are proposed from the aspects of catalyst preparation, structure analysis and catalytic performance.

Key words: catalyst, sintering, deactivation, sintering-resistant strategies

摘要：

高温反应环境下金属催化剂易发生烧结，从而导致其活性降低甚至失活。因此，提高其热稳定性是多相催化的重大挑战。本文综述了金属催化剂以颗粒迁移和Ostwald熟化为主的两种烧结机制，整理了通过颗粒粒径分布、颗粒生长动力学、原位透射电镜观测、实验与计算预测四种判断烧结机制的方法；指出温度、化学势、催化剂自身物性是影响烧结的主要因素。其中，温度影响金属颗粒的动能，是引起烧结的主要物理因素；化学势大小受金属与载体间相互作用影响，是影响烧结的化学因素之一。同时围绕金属-载体相互作用、空间限域及其他新颖的抗烧结策略，总结了近年来在提高催化剂抗烧结性能方面的研究进展。最后从催化剂制备、结构分析和性能测试方面，提出了基于抗烧结金属催化剂研究及构建的发展方向。

关键词: 催化剂, 烧结, 失活, 抗烧结策略