Fe–Cu Bimetallic Catalysts for Selective CO2 Hydrogenation to Olefin-Rich C2+ Hydrocarbons

This paper reports on Fe–Cu bimetallic catalysts supported on γ-alumina for selective CO2 hydrogenation to olefin-rich C2+ hydrocarbons. A strong synergetic promoting effect on C2+ hydrocarbon synthesis was observed over Fe–Cu bimetallic catalysts when the Cu/(Cu + Fe) atomic ratio was 0.17. Compared to monometallic Fe catalyst, the Fe–Cu bimetallic catalyst significantly enhances C2–C7 hydrocarbon formation and suppresses the formation of undesired CH4. The addition of K into Fe–Cu bimetallic catalysts inhibits the methanation and further enhances the formation of C2+ hydrocarbons in the meantime. The synthesis of olefin-rich C2–C4 hydrocarbons from CO2/H2 was achieved by using K-promoted Fe–Cu/Al2O3 catalysts with higher K/Fe atomic ratios (e.g., K/Fe ≥ 0.5), where the selectivity of C2–C4 olefin contents was even higher than K-promoted Fe–Co catalysts under the same reaction conditions.