Nanoparticle-enabled integration of air capture and conversion of CO 2 .

Integrating air capture and conversion of CO 2 is key to realizing energy sustainability. However, current integration approaches require high temperature and pressure, making them energy intensive. Here, we demonstrate a nanoparticle (NP) catalysis approach for the hydrogenation of alkyl carbonate, an intermediate obtained from the CO 2 capture process, to formate, achieving one-pot air capture and conversion of CO 2 under ambient conditions. The capture is realized in an ethylene glycol (EG) solution of KOH (EG-KOH) at room temperature, where CO 2 is selectively converted into HO-CH 2 CH 2 -O-COOK (∼100% conversion). This carbonate is then hydrogenated using ammonia borane (under ambient pressure and at 50 °C) to formate (HCOOK) (>90% yield) in the presence of a stable Pd NP catalyst with EG being regenerated. Atomistic simulations suggest that the CO 2 absorption process in the EG-KOH solution is energetically stable, and the catalyst surface provides the reaction site to break the C-O bond in the -O-COOK structure, enabling the hydrogenation of the alkyl carbonate to formate and the regeneration of EG. Our study provides a promising NP-catalysis approach for air capture and conversion of CO 2 into value-added chemicals/fuels under ambient conditions.