Aerobic oxidation of ethylbenzene to acetophenone over mesoporous ceria–cobalt mixed oxide catalyst.

Mesoporous ceria–cobalt (Ce_0.9Co_0.1O₂, Ce_0.8Co_0.2O_2, and Ce_0.7Co_0.3O₂) mixed oxides, ceria (CeO₂), and cobalt oxide (Co₃O₄) catalysts were prepared through modified template-assisted method and employed in oxidation of ethylbenzene with molecular oxygen (O₂) without solvent and additives. Prepared catalysts were characterized by various physicochemical characterization techniques. The XRD results showed the formation of solid solutions in cobalt-doped ceria samples. The XPS results indicated the presence of more Ce³⁺ ions and surface adsorbed oxygen. H₂-TPR profiles revealed a remarkable improvement in the redox behavior of ceria with the doping of cobalt into the ceria lattice. TEM and N₂ adsorption studies showed mesoporous nature of materials. Among the prepared catalysts, Ce_0.9Co_0.1O₂ showed far better activity for oxidation of ethylbenzene with 60% conversion and 87% selectivity toward acetophenone. This is attributed to facile redox behavior, more surface adsorbed oxygen species, and larger surface area of the catalyst and considered as crucial factors to improve the catalytic activity. Mesoporous ceria–cobalt (Ce_0.9Co_0.1O₂) mixed oxide efficiently catalyzed the aerobic oxidation of ethylbenzene to acetophenone without solvent with good conversion and selectivity. [ABSTRACT FROM AUTHOR]