High-Performance Fe–MoS ₂ Electrocatalyst for Efficient Nitrate Reduction to Ammonia: Synergistic Design for Sustainable Ammonia Production

The electrochemical reduction of nitrate (NO₃ ^-) to ammonia (NH₃) offers a promising route for both environmental remediation and sustainable ammonia production, yet current catalysts are limited by low efficiency and selectivity. Inspired by the active sites of nitrate reductase enzymes, this study reports the development of a high-performance electrocatalyst based on iron atoms supported on molybdenum disulfide nanosheets (Fe-MoS₂), deposited on carbon felt. The Fe-MoS₂ catalyst demonstrates a synergistic effect, achieving superior selectivity and productivity for NH₃ synthesis from nitrate under neutral pH and realistic wastewater conditions (500 ppm of NO₃ ^-). Electrochemical testing reveals a maximal Faradaic efficiency of 80% at - 0.53 V versus the reversible hydrogen electrode (RHE) and a peak NH₃ yield rate of 411 μg h^-1 cm^-2 at - 0.98 V versus RHE. The straightforward synthesis of the catalyst via a two-step electrodeposition and drop-casting technique ensures scalability and cost-effectiveness, addressing practical implementation challenges. Comparative studies with single-component catalysts (MoS₂ or Fe alone) confirm the enhanced performance of the Fe-MoS₂ system. Structural and electrochemical characterizations supported by atomistic simulations elucidate the morphology of the catalyst and active sites, while intermediate analysis provides insight into the reaction pathway.