Metalloporphyrin Frameworks to Encapsulate Copper Oxides for Boosting Ethylene Production in Neutral Electrolyte

Abstract

AbstractElectrochemical carbon dioxide reduction (eCO2R) in neutral electrolytes represents a viable solution for alleviating energy and carbon losses associated with carbonate formation, but limited by suboptimal C2+ selectivity and productivity owing to the higher C−C coupling kinetic barrier in such media. To address the issue, here Cu2O nanocubes are encapsulated within metalloporphyrin frameworks to create a benign microenvironment for C−C coupling, with the best catalyst of Cu2O@Cu−TCPP(Co) demonstrating a maximal C2H4 and C2+ FE of 54 ± 2% and 69 ± 4%, respectively, at 500 mA cm−2 in 1 M KCl. Comprehensive structural and spectrometric characterizations utilizing in situ attenuated total reflectance surface‐enhanced infrared absorption spectroscopy (ATR−SEIRAS), in situ X‐ray absorption spectroscopy (XAS), operando Raman, and high‐resolution transmission electron microscopy (HR−TEM) unveil that the high CO2 adsorption endowed by the metal‐organic framework (MOF) overlayer, high CO concentration yield by metalloporphyrins, high local pH rendered by spatial confinement, as well as the highly dispersed Cu crystallites exposing (200) facets synergistically contribute to the asymmetric C−C coupling of *CO and *COH intermediates in favor of C2+ production. Orchestrating the active moieties in a concerted fashion, this study offers a paradigm for the design of eCO2R catalysts in neutral electrolytes.