Boosting light olefin selectivity in CO₂ hydrogenation by adding Co to Fe catalysts within close proximity

Direct conversion of carbon dioxide (CO₂) into lower olefins (C₂-C₄⁼) is highly attractive as a sustainable production route for its great significance in greenhouse gas emission control and fossil fuel substitution. Fe-based catalysts have been extensively studied in CO₂ hydrogenation, which usually show unsatisfactory selectivity toward lower olefins. Here we present a high-dispersion catalyst precursor CoFe₂O₄ with Na (Na-CoFe₂O₄) that offers C₂-C₄⁼ space time yield as high as 2.88 μmol_C2-C4= g_cat⁻¹ s^-1 and olefin to paraffin ratio about 6 at CO₂ conversion higher than 41 %. High dispersion and the intimate contact between Fe and Co sites help inhibit the formation of methane, and favor a higher selectivity of C₂+ hydrocarbons, especially lower olefins. The presence of Na further promotes chain growth and suppresses the direct hydrogenation of Fe-(CH₂)_n intermediates. A superior stability over 100 h was observed, demonstrating the promising potential of this catalyst for industrial applications.