Built‐in Axial Electric Field‐Driven Electron‐Rich Monomolecular Co Sites for Promoting CO ₂ Electroreduction to CO Over Ultrawide Potential Window

Abstract

Abstract Using renewable electricity to convert CO 2 into CO offers a sustainable route to producing a versatile intermediate to synthesize various chemicals and fuels. However, the conversion at scale is largely constrained owing to the lack of potential‐universal feasibility. Here, we developed an electrocatalyst featuring CoPc anchored ZnO with rich oxygen vacancies (CoPc@ZnO v ), thus improving the activity and selectivity of CO 2 ‐to‐CO conversion. Notably, the FEco of CoPc@ZnO v remains above 90% over an ultrawide potential window of 1.3 V (−0.7 to −2.0 V versus RHE) in H‐type cell, 1.40 V (−0.4 to −1.8 V versus RHE) in flow cell and 1.0 V (low cell voltages of 2.0–3.0 V) in the MEA device, surpassing those of previously reported molecular CoPc‐based electrocatalysts and even most single metal site materials. Density functional theory calculations combined with in‐situ spectroscopies reveal that the built‐in axial electric field arising from the p–n junction rectification effect could drive electron‐rich single Co‐N 4 sites with asymmetric charge distribution and geometric curvature, which promotes *COOH formation (i.e., strong CO 2 adsorption, rapid H 2 O dissociation and proton supply), *CO desorption and as well suppresses the hydrogen evolution reaction, thus favoring the production of CO via CO 2 RR over ultrawide potential windows. This work presents a novel catalyst design strategy of asymmetrical monomolecular Co‐N 4 sites based on the built‐in axial electric field theory, as well as a new way to tune the out‐of‐plane polarization for improved catalytic performance.