Efficient ceria – silica catalysts for BTX oxidation : probing the catalytic performance and oxygen storage.

Abstract

This paper describes a systematic investigation on the synthesis of CeO2 supported on SiO2 by two different methods: (i) the in situ incorporation of CeO2 onto MCM-41 and (ii) wet impregnation. We were interested in investigating how the CeO2 preparation could influence their physicochemical properties and catalytic performances towards the benzene, toluene, and o-xylene (BTX) oxidation reactions. Our results showed that the catalytic performances were strongly dependent on the synthetic approach, in which the CeO2–MCM-41 material prepared by the in situ incorporation showed better BTX oxidation activities than the CeO2-based catalysts prepared by conventional wet impregnation. This result could be assigned to the higher specific surface area, better interaction between CeO2 and the support, improved Ce4+/Ce3+ redox process, and higher concentration of oxygen vacancies as enabled by the in situ approach. The influence of CeO2 content in the ordering of the SiO2 mesoporous structure was also demonstrated.