Carbon nanosphere-encapsulated Fe–Co catalysts for CO2 hydrogenation

The catalytic hydrogenation of CO2 to light olefins provides a promising route for converting greenhouse gases into value-added chemicals. In this work, a series of carbon nanosphere (CNS)-encapsulated Fe–Co core–shell catalysts with varying Fe/Co molar ratios were synthesized via resorcinol–formaldehyde polymerization followed by carbonization and evaluated for CO2 hydrogenation under atmospheric pressure. Among the catalysts investigated, CNS–Fe1Co2 exhibited comparatively improved catalytic performance, showing higher CO2 conversion and enhanced selectivity toward C2–C4 olefins relative to the monometallic CNS–Fe and CNS–Co catalysts. Structural characterization suggested the formation of a CNS-confined Fe–Co core–shell structure. XRD and XPS analyses indicated progressive transformation of Fe oxide species into carburized Fe-containing phases during reaction, while H2-TPR results suggested strong interaction between Fe and Co species. Raman spectroscopy and TGA results further indicated that the graphitic CNS framework remained largely preserved after reaction. The combined results suggest that Fe–Co interaction together with CNS confinement influences catalyst reducibility, carburization behavior, and structural stability during CO2 hydrogenation.