摘要
负载型金属催化剂是一类重要的催化材料,在石油炼制、环境保护以及材料合成等领域起着重要的作用。然而,由于活性金属在反应环境下容易烧结团聚,以致活性降低乃至失活,因此,如何提高其热稳定性成为负载型金属催化剂研究的一个关键问题。概述了催化剂的金属团聚成因及其稳定机制。简要介绍了Ostwald效应以及颗粒合并长大两种团聚模型,从热力学角度解释了导致催化剂烧结团聚的原因。总结了现阶段几种提高负载型金属催化剂热稳定性能的方法,具体包括以包覆封装隔离为原理的物理方法,以及以形成化学键为基础的化学方法,可为进一步开发高热稳定性的负载型金属催化剂提供借鉴。
Supported metal catalysts play a pivotal role for many reactions in industrial processes, including petroleum refining, environmental protection and materials synthesis. However, the active metal centers suffer from severe sintering under real working condition, which will subsequently lead to a loss of its activity. Therefore, the stability of supported catalysts becomes a critical issue to its catalytic application. In this review, the aggregation and stabilization mechanisms of supported metal catalyst were briefly discussed according to the two different aggregation models of metal particles, i.e., Ostwald ripening and coalescence of smaller particles. Accordingly, the corresponding stabilization strategies, including physical methods based on encapsulation and chemical methods by forming chemical bonds, were introduced. The understanding of stabilization mechanism of supported metal catalyst would not only benefit for the development of new catalysts with promoted stability, but also provide theoretical guidance for the optimization of industrial catalysts.
出处
《化工学报》
EI
CAS
CSCD
北大核心
2016年第1期73-82,共10页
CIESC Journal
基金
国家自然科学基金项目(21203182
21476226
21506204)~~
关键词
负载型金属催化剂
稳定性
团聚
烧结
稳定机制
稳定策略
supported metal catalysts
stability
aggregation
sintering
stabilization mechanism
stabilization strategy
