Fe-Cu Bimetallic Catalysts for Selective CO2 Hydrogenation to Olefin-Rich C-2(+) Hydrocarbons

This paper reports on Fe-Cu bimetallic catalysts supported on gamma-alumina for selective CO2 hydrogenation to olefin-rich C-2(+) hydrocarbons. A strong synergetic promoting effect on C-2(+) 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 C-2-C-7 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 C-2(+) hydrocarbons in the meantime. The synthesis of olefin-rich C-2-C-4 hydrocarbons from CO2/H-2 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 C-2-C-4 olefin contents was even higher than K-promoted Fe-Co catalysts under the same reaction conditions.