Efficient Electrochemical Reduction of CO2 to Formate in Methanol Solutions by Mn Functionalized Electrodes in the Presence of Amines

Carbon cloth electrode modified by covalently attaching a manganese organometallic catalyst is used as cathode for the electrochemical recuction of CO2 in methanol solutions. Six different amines are employed as co-catalyst in millimolar concentrations, which coupled to the increased solubility of CO2 in methanol enhance the formate production, switch the selectivity toward formate anion, and in the case of pentamethyldiethylentriamine (PMDETA) resulted in an impressive TONHCOO– of 2.8×104. We demonstrate that the protonated PMDETA is formed in methanol solution by simply bubbling CO2, which is the responsible for a barrierless transformation of CO2 to formate via the reduced form of the Mn catalyst covalently bonded to the electrode surface. These findings pave the way for more efficient transformation of CO2 into liquid fuel and shed light on the electrochemical mechanism