Single-atom Co alloyed Ru for electrocatalytic nitrite reduction to ammonia

Electrochemical converting NO₂⁻ into NH₃ (NO₂RR) holds an enormous prospect to attain efficient NH₃ electrosynthesis and polluted NO₂⁻ mitigation. Herein, we report single-atom Co alloyed Ru (Co₁Ru) as an efficient and durable NO₂RR catalyst. Extensive experimental and theoretical investigations reveal that single-atom Co alloying of Ru enables the construction of Co₁-Ru heteronuclear active sites to synergistically promote NO₂⁻ activation/hydrogenation while suppressing the competitive H₂ evolution, rendering the greatly enhanced activity and selectivity of Co₁Ru towards the NO₂RR. Consequently, Co₁Ru assembled within a flow cell exhibits an impressive NH₃ yield rate of 2379.2 μmol·h⁻¹·cm⁻² with an NH₃-Faradaic efficiency of 92% at a high current density of 415.9 mA·cm⁻², which is among the highest NO₂RR performances reported to date.