Enhanced Urea Electrosynthesis via Nonbonding Interaction between Neighboring In and Cu Single-Atom Sites

Electrocatalytic coupling of carbon dioxide (CO₂) and nitrogen-containing species (e.g., N₂, NO₃^-) to produce urea offers a sustainable option to traditional industrial systems. However, the selectivity and yield rate of urea remain unsatisfactory. Herein, a dual-metal single-atom InCu catalyst, with adjacent In and Cu single-atom pairs dispersed on carbon black, was prepared as an efficient electrocatalyst for the synthesis of urea. Due to the synergism between neighboring In and Cu sites, it exhibits significantly enhanced performance for urea generation from CO₂ and NO₃^-, reaching a Faradaic efficiency (FE) of 52.5% in a flow cell with a corresponding yield rate of 1882.7 μg h^-1 mg_cat^-1, surpassing both the In single-atom catalyst and Cu single-atom catalyst. Additionally, the InCu catalyst exhibits catalytic activity in coupling CO₂ with N₂. In situ Fourier-transform infrared spectroscopy (FTIR) results combined with theoretical simulations reveal that the single In atom can be activated by its neighboring Cu site via a nonbonding interaction, which facilitates the generation of a key *ONCO intermediate and thereby accelerates C-N coupling in urea production. This work proposes a strategy to synthesize a single-atom catalyst with multimetal species and emphasizes the importance of the synergistic effect between neighboring single-atom pairs for boosted urea electrosynthesis.