Electrochemical Reduction of CO 2 to CO by a Co‐N‐C Electrocatalyst and PEM Reactor at Ambient Conditions

Abstract Selective electrochemical reduction of CO 2 to CO was studied using a new electrocatalyst and a gas‐electrolysis cell utilized a polymer‐electrolyte‐membrane (PEM) reactor. A selective and active electrocatalyst was prepared by partial pyrolysis of electrocatalyst precursor of Co‐4,4′‐dimethyl‐2,2’‐bipyridine (4,4’‐dmbpy) supported on Ketjenblack (KB). A heat‐treatment temperature of the Co‐4,4’‐dmbpy/KB significantly influenced on its electrocatalytic activity and 573∼673 K treatments were suitable for a selective CO 2 reduction. A high performance of CO formation (331 μmol h −1 cm −2 , 217 TOF(Co) h −1 ) at 20 mA cm −2 with 72 % faradic efficiency was performed by using the optimized Co‐4,4’‐dmbpy/KB electrocatalyst at –0.75 V (SHE) and 273 K. Electrochemical silent Co species in CV studies promoted electrochemical reduction of CO 2 to CO.