Bidirectional Nitrogen Neutralization via Coupled Electrocatalytic Processes of Nitrate Reduction and Hydrazine Oxidation

Abstract The electrocatalytic coupling of the nitrate reduction reaction (NO₃⁻RR) and the hydrazine oxidation reaction (HzOR), denoted as NO₃⁻RR||HzOR, not only holds promise for the synthesis of high‐value‐added products (such as NH₃) but also facilitates bidirectional nitrogen neutralization. Here, the synthesis of sponge‐like porous nitrogen‐doped carbon encapsulated Cu nanoparticles electrocatalysts is presented for the electrochemical NO₃⁻RR||HzOR. Substituting the traditional oxygen evolution reaction (OER) with the HzOR as the anode reaction notably accelerates the kinetic process of NH₃ synthesis via NO₃⁻RR. Moreover, the spatial confinement of Cu nanoparticles within a sponge‐like porous nitrogen‐doped carbon (NDC) structure not only addresses the aggregation and detachment issues of Cu NPs from the catalyst support surface but also effectively modulates the electronic structure of Cu NPs through electronic interactions between NDC and Cu NPs. This, in turn, enhances the adsorption and activation of nitrate ions. Consequently, the combined advantages of optimized surface electronic structure and spatial confinement of Cu NPs significantly improve the activity and stability for the electrocatalytic NO₃⁻RR to NH₃. This work offers significant reference value for sustainable nitrogen neutrality development by leveraging a mild, energy‐efficient, and environmentally friendly electrocatalytic process that concurrently eliminates nitrogen pollutants in both high and low oxidation states.