Solvent‐ and Catalyst‐Free Carbon Dioxide Capture and Reduction to Formate with Borohydride Ionic Liquid
Loris Lombardo, Heena Yang, Kun Zhao, Paul J. Dyson, Andreas Züttel
Abstract
Abstract The metal‐ and solvent‐free capture and reduction of large amounts of CO 2 to formate under ambient conditions is achieved by combining a pyrrolidinium‐based ionic liquid with a borohydride anion. This material demonstrates one of the highest CO 2 capacities at room temperature and 1 bar with up to 1 g g −1 IL . CO 2 gas reacts with the BH 4 − anion to give triformatoborohydride, [HB(OCHO) 3 ] − . The reaction occurs without loss in capacity at low CO 2 concentration (6 vol % diluted with N 2 ). The thermodynamics and kinetics of the reaction were monitored by using a magnetic suspended balance. In addition, more than 1 mol mol −1 is captured and reduced if air is used as a CO 2 source. The product can be then treated with HCl to give formic acid and the corresponding ionic liquid chloride, which can be recycled. This ionic liquid borohydride demonstrates great potential as a CO 2 absorber and reducer to produce alternative fuels.