Cobalt-Nickel Catalysts for Selective Hydrogenation of Carbon Dioxide into Ethanol

Selective hydrogenation of CO2 into valuable ethanol proceeds by the coupling of appropriate C-1 intermediates to form C-2-oxygenates. Matching the different C-1 intermediates is crucial for this process but is difficult to control. We found that incorporation of nickel species into the cobalt catalyst could boost the formation of relatively stable *CHx intermediate from CO2 hydrogenation, which significantly avoids an occurrence of methanation. The *CHx species subsequently insert into the *HCOO, another intermediate that is easily formed, to produce C-2-oxygenates. Following this pathway, the optimized catalyst, Co0.52Ni0.48AlOx, gives the ethanol yield at 15.8 mmol g(cat)(-1) with selectivity at 85.7% in the CO2 hydrogenation at 200 degrees C for 12 h, which even outperforms those of noble metal catalysts.