Embedding Pure‐Phase Fe₃C Functional Sites Into Biochar Matrix for Multi‐Scenario Electrocatalytic Ammonia Synthesis and Energy Conversion Utilization

Abstract The rational design and development of application‐oriented advanced functional catalysts is crucial for facilitating the conversion of nitrogen oxides into high‐value ammonia. Herein, biomass derived from the pomelo peel, which is rich in metal complex groups and exhibits a metallic foam‐like framework, is utilized as a precursor. Iron carbide (Fe 3 C) active sites are incorporated into the locally 2D, and globally 3D biochar structure, enabling the multi‐scenario green synthesis of ammonia and integrated energy utilization. As a catalyst, Fe 3 C‐BC achieved an ammonia yield rate of up to 102120.53 µg h⁻¹ mg cat ⁻¹, with a maximum ammonia selectivity of 100%. A flow‐based electrolysis system featuring Fe 3 C‐BC not only facilitated the continuous synthesis of ammonia but also enhanced solar energy harvesting. Additionally, a nitrate battery employing Fe 3 C‐BC as the anode exhibited high energy output and enabled self‐driven ammonia synthesis, offering novel insights and operational solutions for the future of green ammonia production. Density‐functional‐theory calculations confirmed that Fe 3 C actively reduces the energy barrier of key steps in the eNitRR process while accelerating water dissociation to promote sustained proton supply. These findings collectively provide a promising foundation for advancing the green synthesis of ammonia, emphasizing both efficient catalytic performance and sustainable energy integration.