Fe based core-shell model catalysts for the reaction of CO2 with H2

Fe@SiO(2)core-shell model catalysts were investigated for the conversion of CO(2)and H(2)into CH4, CO and H2O. For evaluation of the effect of core size on the catalytic activity, samples with Fe particle sizes of 4, 6 and 8 nm were prepared. Fresh and spent catalysts were thoroughly characterized by X-ray diffraction,Fe-57 Mossbauer spectroscopy, transmission electron microscopy, temperature programmed hydrogenation and X-ray photoelectron spectroscopy. As a result, the yield of the major product CO as well as CH(4)was increased with Fe core size. Additionally, growing Fe cores led to stronger carburization and higher amount of reactive carbide entities, which drive the CH(4)formation. Finally, formation of inactive bulk carbon deposition is strongly suppressed for the core-shell catalysts in comparison to bulk iron oxide catalysts used for CO(2)hydrogenation.