Pre‐Activation of CO2at Cobalt Phthalocyanine‐Mg(OH)2Interface for Enhanced Turnover Rate

Abstract

AbstractCobalt phthalocyanine (CoPc) anchored on heterogeneous scaffold has drawn great attention as promising electrocatalyst for carbon dioxide reduction reaction (CO2RR), but the molecule/substrate interaction is still pending for clarification and optimization to maximize the reaction kinetics. Herein, a CO2RR catalyst is fabricated by affixing CoPc onto the Mg(OH)2substrate primed with conductive carbon, demonstrating an ultra‐low overpotential of 0.31 ± 0.03 V at 100 mA cm−2and 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−2for 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)2plays a pivotal role to enhance the CO2RR kinetics by facilitating the first‐step electron transfer to form anionic *CO2−intermediates. DFT calculations further elucidate that introducing Lewis acid sites help to polarize CO2molecules 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 CO2RR.