Mechanistic insight into electron orientation by tailoring Ni–Cu atom-pairs for high-performance CO2 electroreduction

The electrochemical CO2 reduction reaction (CO2RR) is a promising solution for addressing global issues related to carbon neutrality and energy shortage. However, it is hindered by the high thermal stability of CO2 and competitive hydrogen evolution reaction, which lead to low efficiency and selectivity. Herein, a Ni–Cu atom-pair catalyst with well-defined electron orientation has been tailored for electrocatalytic CO2RR. In particular, the tailored Ni/Cu0.38–covalent triazine framework catalyst exhibited extremely high catalytic activity with high faradaic efficiency (99.82% at −1.1 V vs. reversible hydrogen electrode, RHE) and turnover frequency (5116 h−1 at −1.1 V vs. RHE). To the best of our knowledge, this is a diatomic catalyst with the lowest reported metal concentration and excellent efficiency and selectivity. Density functional theory calculations and experimental results further revealed that the adsorption of CO2 was enhanced, while the electron orientation from the Cu site to Ni site reduced the antibonding orbital coupling between Ni and C atoms in CO2, thereby breaking the protonation energy barrier and providing high catalytic efficiency. Moreover, the enrichment of electrons from the electrolyte as well as the accumulation of *H at Cu sites was essential for improving CO selectivity.