Rational design of metal-based nanocomposite catalysts for enhancing their stability in solid acid catalysis.

The use of supported metal-based heterogeneous catalysts is very ubiquitous in the modern chemical industry. Although high reactivity has been achieved, conventional supported metal-based heterogeneous catalysts commonly face the problem of rapid deactivation, generally involving leaching, poisoning or sintering of the active metal species, which is particularly serious in various solid acid catalysis processes. To overcome these drawbacks, different strategies have been adopted, including strengthening metal-support interactions, confining metal species in various porous materials, or coating the active metal nanoparticles with thin shells, which may generate effective metal-based nanocomposite catalysts with enhanced stability. In this feature article, we summarize our recent work on the design of some metal-based nanocomposites possessing yolk-shell, core-shell or other confined structures for enhanced catalytic applications in several important acid catalysis reactions, such as cycloaddition of CO, epoxidation of olefins, acylation of aromatic compounds, and transesterification/carbonylation synthesis of organic carbonates. More attention is paid to the design and preparation strategy of metal-based nanocomposite catalysts, which can generate unique catalytically active and stable metal sites for meeting the tough requirements of a specific catalytic reaction. Finally, the existing challenges and the future directions for metal-based nanocomposite catalysts with respect to the preparation strategies and catalytic application prospects are proposed.