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 Fouriertransform 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.