High-Efficiency Electrocatalytic Reduction of N₂O with Single-Atom Cu Supported on Nitrogen-Doped Carbon

Nitrous oxide (N₂O) is a potent greenhouse gas with a high global warming potential, emphasizing the critical need to develop efficient elimination methods. Electrocatalytic N₂O reduction reaction (N₂ORR) stands out as a promising approach, offering room temperature conversion of N₂O to N₂ without the production of NO_x byproducts. In this study, we present the synthesis of a copper-based single-atom catalyst featuring atomic Cu on nitrogen-doped carbon black (Cu₁-NCB). Attributed to the highly dispersed single-atom Cu sites and the effective suppression of the hydrogen evolution reaction, Cu₁-NCB demonstrated an optimal N₂ faradaic efficiency (82.1%) and yield rate (3.53 mmol h^-1 mg_metal^-1) at -0.2 and -0.5 V vs RHE, respectively, outperforming previously reported N₂ORR electrocatalysts. Further, a gas diffusion electrode cell was employed to improve mass transfer and achieved a 28.6% conversion rate of 30% N₂O with only a 14 s residence time, demonstrating the potential for practical application. Density functional theory calculations identified Cu-N₄ as the crucial active site for N₂ORR, highlighting the significance of the unsaturated coordination and metal-support electronic structure. O-terminal adsorption of N₂O was favored, and the dissociative adsorption (*ON₂ → *O + N₂) was the rate-determining step. These findings reveal the broad prospects of N₂O decomposition via electrocatalysis.