Tailoring local structures of atomically dispersed copper sites for highly selective CO₂ electroreduction

Abstract

Abstract Atomically‐dispersed copper sites coordinated with nitrogen‐doped carbon (Cu–N–C) can provide novel possibilities to enable highly selective and active electrochemical CO 2 reduction reactions. However, the construction of optimal local electronic structures for nitrogen‐coordinated Cu sites (Cu–N 4 ) on carbon remains challenging. Here, we synthesized the Cu–N–C catalysts with atomically‐dispersed edge‐hosted Cu–N 4 sites (Cu–N 4 C 8 ) located in a micropore between two graphitic sheets via a facile method to control the concentration of metal precursor. Edge‐hosted Cu–N 4 C 8 catalysts outperformed the previously reported M–N–C catalysts for CO 2 ‐to‐CO conversion, achieving a maximum CO Faradaic efficiency (FE CO ) of 96%, a CO current density of –8.97 mA cm –2 at –0.8 V versus reversible hydrogen electrode (RHE), and over FE CO of 90% from –0.6 to –1.0 V versus RHE. Computational studies revealed that the micropore of the graphitic layer in edge‐hosted Cu–N 4 C 8 sites causes the d ‐orbital energy level of the Cu atom to shift upward, which in return decreases the occupancy of antibonding states in the *COOH binding. This research suggests new insights into tailoring the locally coordinated structure of the electrocatalyst at the atomic scale to achieve highly selective electrocatalytic reactions.