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

Abstract

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 μmolC2-C4= gcat−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.