(70b) Highly Efficient Formate Production By Hydrogenation of Captured CO2

Climate change resulting from the emission of CO2 has become a widespread concern in the recent years. Carbon Capture and Storage (CCS) is a promising technology that has the potential to address the 40% of emission emanating from large-point sources such as power plants. The utilization of CO2 as a raw material in the synthesis of chemicals and liquid energy carriers offers a direct way to mitigate the increasing CO2 build-up but catalytic reduction of CO2 to fuels or value added chemicals is still one of the greatest challenges. Recently, increasing efforts have been devoted to the transformation of CO2 into value added substances such as formic acid or formates, which are highly attractive as commodity chemicals used as preservative and antibacterial agents, as well as clean sources for H2 generation. Herein, an effective low-temperature process of hydrogenating liquid ammonia or amine captured CO2 over supported palladium nano-catalysts, which can leverage the existing industrial infrastructure to produce value-added formate by utilizing the CO2 derivatives in the commercial CCS process, has been developed. For the first time, we found that the yield of formates is highly dependent on the ethyl carbonate ion intermediates in a solution of ammonium carbonate or amine-CO2 adduct. We further designed the rechargeable â??hydrogen batteryâ? based on the redox equilibrium between liquid ammonia captured CO2 and the corresponding ammonium formates, where hydrogen was stored in chemical bonds. The stored hydrogen can be catalytically liberated under mild conditions as the feed to fuel cells for regenerating electricity.