Abstract
The electrochemical synthesis of urea from nitrate (NO(3) (-)) and carbon dioxide (CO(2)) presents a sustainable alternative to conventional methods, mitigating pollution and reducing energy consumption. Herein, a rationally designed Ni-Fe bimetallic pyromellitic acid polymer catalyst (Ni-PMDA@Fe) is developed for efficient urea electrosynthesis. This metal-organic polymer provides structural robustness, abundant active sites, and a tunable coordination environment, optimizing C-N coupling kinetics. Ni-PMDA@Fe achieves a urea yield of 449.56 mg h(-1) g(cat) (-1) and a Faradaic efficiency (FE) of 41.06% at -0.5 V(RHE), significantly surpassing monometallic controls (Ni-BDC, Ni-PMDA). Fe incorporation modulates the electronic structure of Ni, enhances charge transfer, and stabilizes key reaction intermediates, enabling synergistic NO(3) (-)/CO(2) coupling. Comprehensive characterization confirms homogeneous Fe doping and a dual-metal-site configuration. Unlike single-atom or monometallic systems, the Ni-Fe dual-site architecture optimally tunes the adsorption kinetics of critical intermediates. The catalyst maintains a FE exceeding 30% over a 30 h stability test, demonstrating robust operational stability. Furthermore, techno-economic analysis (TEA) indicates competitive production costs when powered by renewable energy, highlighting scalability potential. This word demonstrates a practical pathway for sustainable urea synthesis by converting pollutants (NO(3) (-)/CO(2)) into value-added product, thereby contributing to decarbonizing fertilizer production and mitigating nitrogen pollution.