Reprogramming the Microenvironment of Cobalt Phthalocyanine by a Targeted Multifunctional π-Conjugated Modulator Enables Concerted CO2 Electroreduction

Architecting the interfacial microenvironment is highly desirable for achieving enhanced electrochemical CO 2 reduction reaction (CO 2 RR), but it is still a challenge. Herein, a π-conjugated matrix of graphitic carbon nitride/graphene (C 3 N 4 /G) is built to tailor cobalt phthalocyanine (CoPc) into an efficient CO 2 electrocatalyst. The enhanced mechanism of microenvironment-mediated CO 2 RR on CoPc/C 3 N 4 /G is fully distinguished by integrating the experimental and theoretical results. C 3 N 4 /G is energetic for CO 2 enrichment and H 2 O dissociation to produce activated H* species, which enables a ceaseless yet fast power injection into the kinetic process of the CO 2 RR. Meanwhile, the electron structure of Co active sites modulated by C 3 N 4 /G also thermodynamically favors the conversion of CO 2 and intermediates. Consequently, in a flow cell, CoPc/C 3 N 4 /G delivers a high turnover frequency value (50.5 s –1 ), gratifying CO selectivity (∼100%) as well as current density (67.8 mA cm –2 ) at −1.1 V vs RHE, and maintains a Faradaic efficiency for CO above 98% in an ultrawide potential window of over 500 mV, ranking among the state-of-the-art macrocyclic complex-based catalysts currently reported for CO 2 reduction to CO. This work underlines the significance of well-tailored microenvironment design in the electrocatalytic system.