Rapid Fabrication\nof N‑, Cu‑, and Co-Doped\nElectrodes with Strong Electronic Coupling by Cold Plasma for Electrocatalytic\nReduction of Nitrate to Ammonia

Electrochemical NO<sub><i>x</i></sub><sup>–</sup> reduction (NO<sub><i>x</i></sub>RR) is a sustainable technology\nfor ammonia synthesis. The development of a simple, fast, and economical\ncatalytic electrode preparation technique is crucial for large-scale\nammonia synthesis. Herein, we propose a plate-to-plate DBD plasma\nstrategy to synthesize the catalytic electrodes M–N/CP (M =\nCu, Co, Ni, CuCo, and CuNi), achieving in suit codoping of N and bimetals\non carbon paper (CP) at room temperature within 3 h. N-doping improves\nthe metal loading and the NO<sub><i>x</i></sub>RR performance\nby forming N–M bonds. The electronic coupling and synergistic\neffect of Cu and Co sites facilitate the relay conversion of NO<sub>3</sub><sup>–</sup> to NO<sub>2</sub><sup>–</sup> to\nNH<sub>3</sub>. Notably, the NO<sub>3</sub><sup>–</sup> removal\nefficiency of CuCo–N/CP reaches 82%, with NH<sub>3</sub> yield\nrate of 346 μg h<sup>–1</sup> cm<sup>–2</sup>,\nand the faradaic efficiency is as high as 86% at −0.58 V vs\nRHE, which remains competitive in terms of NO<sub><i>x</i></sub>RR performance. Importantly, wet flue gas denitrification and\ndesulfurization coupled with electrocatalytic reduction can convert\nNO<sub><i>x</i></sub> and SO<sub>2</sub> to (NH<sub>4</sub>)<sub>2</sub>SO<sub>4</sub>, Additionally, the maneuverability of\nplasma technology offers the potential for batch preparation of CuCo–N/CP\nelectrodes for electrochemically driven wet denitrification wastewater\nvalorization.