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

Mesoporous ceria-cobalt (Ce0.9Co0.1O2, Ce0.8Co0.2O2 and Ce0.7Co0.3O2) 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 (O-2) 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. H-2-TPR profiles revealed a remarkable improvement in the redox behavior of ceria with the doping of cobalt into the ceria lattice. TEM and N-2 adsorption studies showed mesoporous nature of materials. Among the prepared catalysts, Ce0.9Co0.1O2 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. [GRAPHICS] .

Automated summary

Mesoporous ceria-cobalt mixed oxides, ceria, and cobalt oxide catalysts were prepared using a modified template-assisted method and showed improved activity in the oxidation of ethylbenzene. The catalyst with a composition of Ce0.9Co0.1O2 exhibited the best performance, attributed to its facile redox behavior, increased surface adsorbed oxygen species, and larger surface area.