Selective CO2‐to‐CO Conversion Enabled by Ultrathin Nitrogen‐Modified Graphene Confined Cobalt–Cobalt Oxide Nanocomposites with Prominent Electron Synergy

Abstract

AbstractDeveloping and fabricating cost‐effective materials for efficient thermocatalytic reduction of CO2 to CO under mild conditions is a promising and practical way to sustainable and green low‐carbon energy systems, which remains a challenge. Herein, a facile high‐temperature pyrolysis strategy for the synthesis of efficient ultrathin nitrogen‐modified graphene confined cobalt oxide (CoOx@NG) nanocomposites with prominent electron synergistic effect on inner Co─CoO core and confinement of N‐modified graphene shell is reported. The electronic and/or geometric structures of active metallic Co and coordinatively unsaturated CoO species are modulated by the graphene confinement effect. The electron‐rich N dopant in the graphene shell enhances the surface electron density of the catalyst, thus regulating the adsorption of acidic CO2 molecules. The engineered CoOx@NG shows an outstanding selective CO2‐to‐CO efficiency, with a conversion of 19.5% and a near full CO selectivity at 523 K as well as excellent stability for 150 h on stream. Moreover, the in‐depth insights into the material microstructure, electron synergy, structure‐activity relationships, key intermediate species, and a three‐step reaction mechanism involving the rate‐determining step of C═O bond cleavage for critical *C═O species via 13CO2 isotope and in situ spectroscopy are also demonstrated.