Synergistic FeGe dual sites in Fe13Ge8 Intermetallics boost nitrate reduction to Ammonia.

The electrocatalytic nitrate reduction reaction (NO3RR) provides a promising route for simultaneous nitrate (NO3-) removal and sustainable ammonia (NH3) production. However, this process is limited by complex reaction pathways and sluggish kinetics. Herein, carbon-supported Fe13Ge8 intermetallic compounds (i.e. Fe13Ge8/C) are synthesized via a high-temperature annealing strategy. The obtained Fe13Ge8/C catalyst exhibits an NH3 yield rate of 5.8 mg·h-1·cm-2 and a Faradaic efficiency (FE) of 93% at -0.7 V in 1.0 M potassium hydroxide (KOH), outperforming carbon-supported iron nanoparticles (i.e. Fe/C) and most of the reported noble-metal-free NO3RR electrocatalysts. Density functional theory (DFT) calculations reveal that Fe sites in Fe13Ge8 effectively facilitate the adsorption and activation of NO3-. Meanwhile, Ge sites promote water (H2O) dissociation and active hydrogen (*H) generation, thereby continuously supplying abundant *H for subsequent hydrogenation steps. The synergistic interaction between Fe and Ge dual sites in Fe13Ge8 significantly reduces the energy barrier of the rate-determining step in NO3RR.