Metal and Metal Oxide Supported on Ordered Mesoporous Carbon as Heterogeneous Catalysts

The evolution of model catalyst systems has experienced single-crystal surfaces of different transition metals and different crystal faces, two-dimensional systems with nanoparticles (NPs) deposited on a flat support surface, and three-dimensional systems with NPs loaded into the high-surface-area supports such as ordered mesoporous materials. The latter two systems mimic the nanoparticle properties in industrial catalysts. Ordered mesoporous carbon (OMC) materials play unparalleled roles in catalysis, energy storage, adsorption, chromatographic separation, etc. because of their distinctive structure which allows Knudsen diffusion inside mesopores, the dispersion of loaded metals and oxides, and the embedment of metals inside pore walls. In this review, the synthesis routes of OMC-supported metal or metal oxide catalysts, including hard-templating and soft-templating methods, are briefly introduced. Mass transfer inside the mesopores, reactant chemisorption on the metals, discrimination of the different active species, and the catalytic reaction mechanism of the OMC-supported metal or metal oxide catalysts are systemically summarized, with the highlight of advantages in catalysis occurring inside mesopores. Understanding these molecular-dominated factors provides insight into controlling the highly active and selective catalytic reactions and, therefore, the design of industrial catalysts with a long life.