Coupling of electrocatalytic CO 2 reduction and CH 4 oxidation for efficient methyl formate electrosynthesis

The electrocatalytic carbon dioxide reduction reaction (CO 2 RR) is promising for the conversion of greenhouse gases into value-added chemicals; however, it suffers from limited energy efficiency and product variability. The direct coupling of both cathode and anode products may provide new potential for carbon fixation and chemical electrosynthesis. Herein, we rationally designed a strategy to couple both CH 4 oxidation reaction (CH 4 OR) and CO 2 RR in an integrated electrochemical system for the electrosynthesis of methyl formate. Using a bismuth (Bi) catalyst on the cathode and an IrO 2 nanowire catalyst with Cl − on the anode, CO 2 and CH 4 gases were electrochemically reduced and oxidized into formate and CH 3 Cl, respectively, with industrial-level current densities and high selectivities. The formed HCOO − was transported under an electric field into the anode region and launched a nucleophilic attack on CH 3 Cl to produce methyl formate. This integrated electrochemical cell exhibited outstanding performance for coupling both CO 2 RR and CH 4 OR, including a peak methyl formate production rate of 1660 μmol h −1 cm −2 , an energy efficiency of ∼15.2%, and excellent electrochemical stability at industrial-level current densities.