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 Hägg iron carbide (χ-Fe₅C₂) phase readily through the in situ carburization of iron. [ABSTRACT FROM AUTHOR]