Tuning Co-Cu-Al catalysts and their reaction conditions on the CO2 hydrogenation reaction to higher alcohols under mild conditions

The catalytic conversion of CO2 and H2 into valuable chemicals is a promising alternative to the recent energy and environmental challenges. However, designing an earth-abundant catalyst capable of actively and selectively converting CO2 into desirable products is yet a challenge. Herein, we report on a facile K-Co-Cu-Al catalyst prepared by a coprecipitation method for CO2 hydrogenation to higher alcohols (HAs). We investigated different Co:Cu ratios, reduction temperatures, and reaction conditions (temperature, space velocity, and H2/CO2 ratio) to tune it, enhancing the selectivity and yield of higher alcohols. Co1.8Cu0.9AlOx (1 wt% K), reduced at 400 °C, exhibits a high HAs selectivity of 44.8% (20.8% for ethanol) and space–time yield of 5.54 mmol·h-1·gcat-1 (3.08 mmol·h-1·gcat-1 of ethanol), under mild conditions (250 °C, 30 bar, H2/CO2 ratio of 1.5, and 14200 mL·gcat-1·h-1), which represents one of the best performances among related studies, especially among Co-based catalysts.