Sodium-Containing Spinel Zinc Ferrite as a Catalyst Precursor for the Selective Synthesis of Liquid Hydrocarbon Fuels

A microwave-assisted hydrothermal synthesis produces ZnFe2O4 containing Na residue as a precursor to a CO2 hydrogenation catalyst that displays high CO2 conversion and high selectivity to liquid hydrocarbon products in the gasoline and diesel range with high olefin-to-paraffin ratios. Compared to reference catalysts derived from Fe2O3 and a ZnO-Fe2O3 physical mixture, the ZnFe2O4-derived catalyst contains well-dispersed iron particles with Zn serving as a structural promoter. A profound effect of the residual Na as an electronic promoter is also observed, which improves the selectivity for C5+ hydrocarbons and olefins. The ZnFe2O4-derived catalyst exhibits excellent performance in the CO2 Fischer-Tropsch reaction as it forms the active Hagg iron carbide (-Fe5C2) phase readily through the insitu carburization of iron.