High-Efficiency Electrocatalytic Reduction of N 2 O with Single-Atom Cu Supported on Nitrogen-Doped Carbon.

Nitrous oxide (N 2 O) is a potent greenhouse gas with a high global warming potential, emphasizing the critical need to develop efficient elimination methods. Electrocatalytic N 2 O reduction reaction (N 2 ORR) stands out as a promising approach, offering room temperature conversion of N 2 O to N 2 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 (Cu 1 -NCB). Attributed to the highly dispersed single-atom Cu sites and the effective suppression of the hydrogen evolution reaction, Cu 1 -NCB demonstrated an optimal N 2 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 N 2 ORR electrocatalysts. Further, a gas diffusion electrode cell was employed to improve mass transfer and achieved a 28.6% conversion rate of 30% N 2 O with only a 14 s residence time, demonstrating the potential for practical application. Density functional theory calculations identified Cu-N 4 as the crucial active site for N 2 ORR, highlighting the significance of the unsaturated coordination and metal-support electronic structure. O-terminal adsorption of N 2 O was favored, and the dissociative adsorption (*ON 2 → *O + N 2 ) was the rate-determining step. These findings reveal the broad prospects of N 2 O decomposition via electrocatalysis.