Electronic Transfer‐Driven Optimization of Ni _0.7 Cu _0.3 Mn ₂ O ₄ for Electrocatalytic Nitrate Reduction and Polyethylene Terephthalate Oxidation

Abstract Electrochemical recycling of waste pollutant nitrate (NO ₃ ⁻ ) into high‐value fuels or chemicals is regarded as a green and sustainable approach to addressing global resource utilization issues. Despite considerable efforts, advancements in this area are significantly impeded by the scarcity of high‐performance electrocatalysts. This study introduced a robust Ni‐doped optimized CuMn ₂ O ₄ spinel oxide electrocatalyst (Ni _0.7 Cu _0.3 Mn ₂ O ₄ ) that effectively facilitated the reduction of nitrate to ammonia (NH ₃ ) (NO ₃ RR), achieving a high NH ₃ Faradaic efficiency (FE) (90.8%) and yield (551.3 mmol h ⁻¹ g ⁻¹ ) at a suitable potential. Experimental analysis and theoretical calculations indicated that the in situ incorporation of Ni induced electron transfer from Ni and Cu toward Mn atoms, which changed the electronic microenvironment of the Ni _0.7 Cu _0.3 Mn ₂ O ₄ , thus reduced the reaction barrier for the formation of active hydrogen ( ^* H), subsequently promoted the production and use of ^* H for NO ₃ RR. The change of electronic microenvironment also optimized the d ‐band center of Ni _0.7 Cu _0.3 Mn ₂ O ₄ , thus improved the electron transfer energy of the catalyst to NO ₃ ⁻ , finally improved the adsorption of NO ₃ ⁻ . Moreover, Ni _0.7 Cu _0.3 Mn ₂ O ₄ exhibited excellent catalytic performance for the oxidation of polyethylene terephthalate (PETOR), can selectively generated high‐value‐added formate (FA). NO ₃ RR is coupled with PETOR instead of oxygen evolution reaction, which further improved the resource utilization.