Modulating single‐atom Pd sites with Cu for enhanced ambient ammonia electrosynthesis

The electrochemical reduction of N 2 to NH 3 is emerging as a promising alternative for sustainable and distributed production of NH 3 . However, the development has been impeded by difficulties in N 2 adsorption, protonation of *NN and inhibition of competing hydrogen evolution. To address the issues, we design a catalyst with diatomic Pd-Cu sites on N-doped carbon by modulation of single-atom Pd sites with Cu. The introduction of Cu not only shifts the partial density states of Pd toward the Fermi level but also promote the d-2π* coupling between Pd and adsorbed N 2 , leading to enhanced N 2 chemisorption, activated protonation and suppressed hydrogen evolution. As a result, the catalyst achieves a high Faradaic efficiency of 24.8 ± 0.8% and a desirable NH 3 yield rate of 69.2 ± 2.5 μg h -1 mg cat. - 1 , far outperforming the individual single-atom Pd catalyst. This work paves a pathway of engineering single-atom-based electrocatalysts for enhanced ammonia electrosynthesis.