Balancing Intermediates Formation on Atomically Pd-Bridged Cu/Cu2O Interfaces for Kinetics-Matching Electrocatalytic C─N Coupling Reaction

Abstract

The electrochemical C─N coupling of CO₂ and nitrogenous species provides a promising approach for synthesizing valuable chemicals such as urea, amides, and other C─N compounds. However, the unbalanced formation of C- and N-intermediates results in slow C─N coupling kinetics. Herein, we report an atomically Pd-bridged Cu/Cu₂O (Pd₁–Cu/Cu₂O) catalyst, synthesized through the in situ electrochemical reconstruction of Pd₁–Cu₂Te nanosheets. This catalyst features Pd–Cu dual sites that significantly enhance C─N coupling both thermodynamically and kinetically. The reconstructed Pd₁–Cu/Cu₂O achieves a urea yield rate of 31.8 mmol h⁻¹ g_cat.⁻¹ and a Faradaic efficiency (FE) of 42.2%, along with excellent stability over 100 h. In situ spectroscopic examinations and theoretical calculations disclose that the Pd–Cu dual sites on Pd₁–Cu/Cu₂O modulate the reduction kinetics of CO₂ and NO₃⁻, balance the formation of crucial *CO and *NH₂ intermediates, and lower the energy barrier for C─N coupling, thereby facilitating urea synthesis. Furthermore, the Pd₁–Cu/Cu₂O enables the unprecedented C─N coupling of aniline with CO, resulting in a remarkable acetanilide yield rate of 1021.2 mmol h⁻¹ g_cat.⁻¹ with an FE of 23.7%. This heteroatom bridging strategy offers a new pathway for designing efficient electrocatalyst for the synthesis of C─N coupled compounds.