In Situ Dynamic Reconstruction Asymmetric P─Co─O/OH Sites for Sustainable Gram‐Level Electrocatalytic Ammonia Production

ABSTRACT The electrochemical conversion of nitrite/nitrate (NO x − ) to ammonia (NH 3 ) offers a sustainable route for NH 3 production, particularly coupled with efficient air plasma. However, balancing catalyst activity/stability for gram‐level NH 3 production remains major challenges. In this study, we report a low‐crystallinity phosphorus‐doped cobalt electrode (P─Co/NF) for efficient and stable NH 3 synthesis via NO 2 − reduction, achieving an impressive NH 3 yield rate of 414.51 mg h −1 cm −2 and outstanding long‐term stability of 1000 h. Comprehensive characterizations and theoretical calculations reveal that the dynamically evolved P─Co/Co(OH) 2 heterostructure with asymmetric P─Co─O/OH active sites simultaneously optimizes NO 2 − activation and water dissociation. The synergistic interplay between P─Co and Co(OH) 2 layer facilitates sufficient *H supply and moderate intermediate adsorption, thereby suppressing H 2 evolution. To enable direct air‐to‐NH 3 conversion, a complete system is established by integrating electrocatalysis with microwave plasma and intermittent solar power, achieving an average NH 3 yield of 1.19 g per day with Faradaic efficiency >90%. When scaled up to a 100 cm 2 flow cell, the system delivers an NH 3 production rate of 4.97 g h −1 . This work provides a paradigm for designing dynamic asymmetric sites that overcome activity‐stability tradeoff under industrial‐level current density, paving the way toward the decentralized and sustainable NH 3 production.