Synergistic Electrocatalytic N ₂ Reduction over Asymmetric Heteronuclear Dual Ru‐Fe Sites

Abstract The scaling relationship limit poses a significant challenge in single‐atom catalysts (SACs) for reactions involving multi‐intermediate interactions, such as the electrocatalytic nitrogen reduction reaction (eNRR) for ammonia synthesis. To overcome this limitation, a heteronuclear dual Ru‐Fe sites on N,S‐codoped Ti ₃ C ₂ T _x nanosheet (referred to as Fe ₁ ‐N^S‐Ru ₁ /Ti ₃ C ₂ T _x ) with precisely designed asymmetric coordination for eNRR is developed. Advanced characterizations verify the unique asymmetric coordination structure where Ru and Fe atoms are individually coordinated to N and S atoms, respectively, with the two metal centers interconnected via bridging N and S atoms. This catalyst achieves remarkable eNRR performance with an NH ₃ yield rate of 32.8 µg h ⁻¹ mg ⁻¹ _cat at −0.55 V and 47.1% Faradaic efficiency at −0.25 V, surpassing its homonuclear analogues by 3.2‐ and 2.3‐fold in activity and ≈3.0‐fold in selectivity. Experimental and theoretical studies reveal a synergistic mechanism, in which Ru sites effectively dissociate H ₂ O to supply protons while the adjacent Fe sites selectively activate N ₂ , effectively decoupling proton supply from N ₂ activation but also benefiting the formation of key intermediate ^* NNH. Additionally, the electronic interaction between Ru and Fe sites also lowers the energy barrier of the rate‐determining step, thereby significantly enhancing catalytic activity and selectivity.