Electrochemical urea synthesis from CO₂ and NO_x⁻ co-electrolysis (EUCN) provides a promising strategy to synthesize urea under ambient conditions. Herein, a homonuclear Cu₂-C₂N diatomic catalyst with Cu₂ dimers on C₂N substrate was developed towards the EUCN. Operando spectroscopic analyses and theoretical simulations reveal that Cu₂ dimers with an optimal axial rotation angle of 45° render the most efficient C–N coupling and hydrogenation, thereby boosting the overall EUCN energetics for urea synthesis. Notably, by integrating plasma-driven air-to-NO_x⁻ conversion, cathodic CO₂ + NO_x⁻ co-electrolysis coupled with anodic glycerol oxidation, the exceptional urea yield rate of 107.2 mmol·h⁻¹·g⁻¹ and Faradaic efficiency of 76.2% were achieved, representing one of the best EUCN performances thus far. The work provides mechanistic EUCN insights into the diatomic catalysts and establishes a sustainable and efficient pathway for urea synthesis.

Electrochemical co-reduction of CO₂ and nitrogen sources (N₂ or NO₃⁻) provides a promising route for ambient urea synthesis, yet suffers from low conversion efficiency or reliance on fossil fuel-derived NH₃/NO₃⁻. Herein, we present an integrated plasma-electrocatalytic route for sustainable urea synthesis from ambient air, which involves the initial plasma-driven air oxidation to form NO_x⁻ and followed by electrocatalytic co-reduction of CO₂ + NO_x⁻ to produce urea. Specially, a bifunctional Bi_SA/a-MoO₃ catalyst (isolated Bi single atom on amorphous MoO₃) was designed to promote both plasma and electrocatalytic processes, consequently achieving the exceptional urea yield rate of 55.9 mmol·h⁻¹·g⁻¹ and Faradaic efficiency of 59.7%. The combined theoretical calculations and in situ spectroscopic measurements reveal the synergy of Bi_SA and unsaturated Mo sites in boosting the C–N coupling of *COOH and *NH₂ intermediates for selective urea formation.

Electrochemical urea synthesis from CO₂ and NO (EUCN) offers a promising route for sustainable urea production, whereas it still suffers from low C-N coupling efficiency and poor selectivity. Herein, atomically dispersed p-block Bi catalyst is explored for highly active and selective EUCN. Theoretical calculations and in situ spectroscopic analyses reveal a unique *CO-mediated C-N coupling mechanism, where isolated Bi sites facilitate CO₂ reduction for *CO formation and enrichment, while *CO-enriched microenvironment boosts subsequent C-N coupling of *CO and *NO to *CONO, a critical C-N intermediate for urea generation, while simultaneously suppressing the competing side reactions. Notably, by pairing cathodic EUCN with anodic glycerol oxidation in a membrane electrode assembly electrolyzer, we achieve a record-high performance with urea yield rate of 86.5 mmol·h^–1·g^–1 and Faradaic efficiency of 52.1%, as well as the outstanding stability for over 200 h electrolysis.

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.

Atomically dispersed Ir confined in amorphous MoO₃ (Ir₁/a-MoO₃) was designed as a high-efficiency catalyst for electrochemical reduction reaction of NO to NH₃ (NORR). Atomic precise characterizations reveal that isolated Ir atoms are immobilized in O-vacancies of amorphous MoO₃ to form Ir₁-O₅ moieties. Theoretical computations demonstrate that single-site Ir₁-O₅ can not only powerfully activate and hydrogenate NO with a near-zero energy barrier, but also exhibit a higher affinity to NO over H adatoms to suppress the competing hydrogen evolution and promote both NORR activity and selectivity. Consequently, Ir₁/a-MoO₃ shows the maximum NH₃ yield rate of 438.8 μmol∙h⁻¹∙cm⁻² and NH₃-Faradaic efficiency of 93.2%, representing one of the most efficient NORR catalysts to date.

Electrochemical NO reduction reaction (NORR) to generate NH₃ emerges as a fascinating approach to achieve both NO pollution mitigation and sustainable NH₃ synthesis. Herein, we demonstrate that single-atomic Cu anchored on MoS₂ (Cu₁/MoS₂) comprising Cu₁-S₃ motifs can serve as a highly efficient NORR catalyst. Cu₁/MoS₂ exhibits an NH₃ yield rate of 337.5 μmol·h⁻¹·cm⁻² with a Faradaic efficiency of 90.6% at −0.6 V vs. reversible hydrogen electrode (RHE). Combined experiments and theoretical calculations reveal that Cu₁-S₃ motifs enable the effective activation and hydrogenation of NO through a mixed pathway and simultaneously retard proton coverage, contributing to the high activity and selectivity of Cu₁/MoS₂ for the NORR.