Catalytic Conversion of CO2 to Formate with Renewable Hydrogen Donors: An Ambient-Pressure and H2-Independent Strategy

Catalytic conversion of CO2 via "transfer hydrogenation" using renewable non-H2 compounds (such as biomass-derived (poly)alcohols) to produce valuable energy-relevant chemicals, is a promising alternative strategy to the traditionally employed "hydrogenation" of CO2 with gaseous H2. However, the CO2-transfer hydrogenation has been explored exceptionally less, and limited but encouraging success has been achieved in recent time by applying high pressure (up to 50 atm) of CO2 gas. For safe and simple operation, ambient-pressure protocols are desirable, and toward this end, suitable catalysts are required. Aiming to this goal, herein we report an efficient Ir–aNHC catalyst (aNHC = an abnormal NHC ligand) to achieve ambient-pressure CO2-transfer hydrogenation catalysis for generating formate salt (HCO2–) at the turnover frequency (TOF) value of 90 h–1 in 12 h of reaction at 150 °C using glycerol as hydrogen source.