Observation of Cobalt Species Evolution in Mesoporous Carbon by In‐Situ STEM‐HAADF Imaging and Related Hydrogenation Process

Abstract Metal decorated‐mesoporous carbons (MMCs) has attractive features from both mesoporous materials (large pore size, high pore volume) and metal species (reactive surface). Cobalt@mesoporous carbon (Co@MC) catalyst was successfully manufactured by mechanochemical synthesis method for hydrogenation of phenol to prepare cyclohexanone. Unlike traditional hard‐templating and soft‐templating methods, the essence of this strategy lies in the combination of carbonization and ligand‐protected metal reduction. By using Fourier transform‐infrared spectroscopy, X‐ray diffraction and N 2 adsorption‐desorption, Co@MC catalyst was well studied. In particular, the effect of calcination temperature in terms of growth and aggregation of cobalt species was detailly explored by in‐situ scanning transmission electron microscopy‐high angle angular dark field. A series of mesoporous carbons with cobalt species readily tuned from clusters to nanoparticles were measured in phenol hydrogenation (Conv. Phenol: >99 %, Sel. Cyclohexanone: >99 %).