Engineering the coordination of Cu–Ni dual-atom catalysts to enhance the electrochemical CO2 overall splitting

Abstract

Designing the coordination environment of heteroatoms around metal sites and optimizing the electronic structure of diatomic metal sites remain significant challenges in achieving efficient CO2 overall splitting. Herein, we report four configurations (Cu/Ni–N4C2, Cu/Ni–N2C4, Cu/Ni–N2C3 and Cu/Ni–N2C2) constructed by precise regulation of the coordination environment around bimetallic atoms. Cu/Ni–N2C2 showed high performance in electrochemical CO2 reduction (ECR) and water oxidation evolution reaction (OER). In the electrochemical CO2 overall splitting reaction, it achieved a Faraday efficiency of CO (FECO) of 98.0% at a low cell voltage of −2.9 V, significantly higher than widely reported values. Moreover, the FECO is above 90% over −2.7 to −4.1 V of cell voltages. Cu/Ni–N2C2 achieved long-term ECR stability of 110 h at −100 mA cm−2. Mechanism studies revealed that the change of coordination environment around the diatomic pairs moves the d-band center of the Ni atom closer to the Fermi level, thereby modulating the adsorption capacity of the catalysts to the reaction intermediates *COOH and *O. This work presents valuable insights into the rational design of diatomic catalysts and elucidates the intricate structure-performance relationship in advancing electrochemical CO2 overall splitting technology and energy-conversion applications.