Pre‐Activation of CO2 at Cobalt Phthalocyanine‐Mg(OH)2 Interface for Enhanced Turnover Rate

Abstract Cobalt phthalocyanine (CoPc) anchored on heterogeneous scaffold has drawn great attention as promising electrocatalyst for carbon dioxide reduction reaction (CO 2 RR), but the molecule/substrate interaction is still pending for clarification and optimization to maximize the reaction kinetics. Herein, a CO 2 RR catalyst is fabricated by affixing CoPc onto the Mg(OH) 2 substrate primed with conductive carbon, demonstrating an ultra‐low overpotential of 0.31 ± 0.03 V at 100 mA cm −2 and high faradaic efficiency of >95% at a wide current density range for CO production, as well as a heavy‐duty operation at 100 mA cm −2 for more than 50 h in a membrane electrode assembly. Mechanistic investigations employing in situ Raman and attenuated total reflection surface‐enhanced infrared absorption spectroscopy unravel that Mg(OH) 2 plays a pivotal role to enhance the CO 2 RR kinetics by facilitating the first‐step electron transfer to form anionic *CO 2 − intermediates. DFT calculations further elucidate that introducing Lewis acid sites help to polarize CO 2 molecules absorbed at the metal centers of CoPc and consequently lower the activation barrier. This work signifies the tailoring of catalyst‐support interface at molecular level for enhancing the turnover rate of CO 2 RR.