Dual Metal-Active Phase for Significantly Enhanced Nitrate-to-Ammonia Electrocatalysis from Dynamic Reconstruction of a CuCo-Based Catalyst

Abstract Electrochemical transformation of nitrate (NO3–) into ammonia (NH3) offers an environmentally sustainable pathway to complete the nitrogen cycle, enabling both green NH3 synthesis and NO3– pollution remediation. Herein, we propose an in situ synergistic reconstruction strategy for fabricating a Cu2O@Co-carbon nanofibers (CNFs) pre-electrocatalyst, integrated with the glycerol oxidation reaction (GOR) to replace the energy-intensive oxygen evolution reaction (OER), thereby significantly reducing energy consumption toward electrocatalytic NO3–-to-NH3 conversion. The potential-dependent reconstruction gives rise to coexisting Co0 and Co(OH)2 species together with active Cu sites. Electrochemical measurements and density functional theory (DFT) calculations support their complementary roles in *H generation and NO3– activation, respectively, thereby promoting the NO3RR while suppressing competing reactions. The resulting catalyst delivers an exceptional NH3 yield rate of 61.0 mg cm–2 h–1 at industrial-level current density, manifesting outstanding catalytic performance. This study offers a novel design principle and a reliable strategy for developing high-efficiency non-noble-metal-based bifunctional electrocatalysts and advanced coupled electrochemical systems.