Sandwich-type Co core@shell nanocomposite (SiO2 @Co@CeO2): Coke resistant catalyst toward CO2 reforming with ethanol

The design of highly efficient catalysts for CO 2 reforming with ethanol is of great interest due to the serious coke deposition and the sintering of active metal. In this work, sandwich-type Co core@shell catalyst (SiO 2 @Co@CeO 2 ) with Co nanoparticles between SiO 2 core and CeO 2 shell was synthesized by strong electrostatic adsorption method. Interestingly, SiO 2 @Co@CeO 2 catalyst exhibited the outstanding activity/stability toward CO 2 reforming of ethanol in comparison with Co-SiO 2 catalyst. A bi-functional mechanism involving active sites on CeO 2 shell was proposed. Indeed, cobalt nanoparticles between SiO 2 core and CeO 2 shell maintained the high dispersion because of the confinement effect, which supplied a stable Co-ceria interface area where the reaction occurred. In addition, CO 2 could readily react with the O vacancies in CeO 2 shell to form surface oxygen species and CO, which allowed a continuous cleaning of coke. These positive factors could make it as an attractive candidate for dry reforming process.