Cooperative relay catalysis over Cu–Fe dual sites via N-intermediate and hydrogen radical pathways for ammonia production

Abstract

Dual-atom catalysts (DACs) offer a powerful platform to investigate synergistic mechanisms in complex electrocatalytic reactions, yet direct experimental validation remains scarce. In this work, we present comprehensive evidence for a cooperative relay mechanism over a Cu–Fe DAC in the electrochemical reduction of nitrate (NO₃⁻RR) to ammonia (NH₃). The spatially adjacent Cu and Fe atoms perform distinct but complementary roles: Cu sites facilitate NO₃⁻ activation and deoxygenation steps, while Fe sites drive stepwise hydrogenations through *H radical-assisted transfer. In situ Fourier-transform infrared (FTIR) spectroscopy, X-ray absorption spectroscopy (XAS), and electron paramagnetic resonance (EPR) collectively capture the evolution of N-containing intermediates and transient *H species, providing direct evidence for the dual-site relay pathway. This work elucidates the mechanistic underpinnings of DACs in NO₃⁻RR and highlights cooperative site-specific catalysis as a promising design strategy for selective nitrogen conversion.