Self‐Supported Catalytic Electrode of CoW/Co‐Foam Achieves Efficient Ammonia Synthesis at Ampere‐Level Current Density

Abstract Conversion of air and water into valuable chemicals of ammonia (NH 3 ) by plasma activation and electrochemical reduction is a promising approach to achieve zero carbon‐emission synthesis of NH 3 . However, designing highly efficient electrochemical catalysts is one of the key challenges in accomplishing this strategy. Herein, a self‐supported cobalt–tungsten alloy supported on cobalt foam (CoW/CF) is developed via a simple and efficient method at room temperature. Surprisingly, the catalyst exhibits ultra‐high NH 3 partial current density (1559 mA cm −2 ), superior NH 3 yield rate (164.3 mg h −1 cm −2 ), and high Faradaic efficiency (98.1%) under the condition of 0.2 M nitrate/nitrite, outperforming most of the reported values of electrosynthesis of NH 3 to the knowledge. The introduction of W makes the Co atom surface electron deficient, which can enhance the adsorption of NO x − and mitigate the excessive bonding of hydroxyl radicals (OH * ) generated during nitrite (NO 2 * ) hydrogenation, thereby reducing the energy barrier of the potential‐determining step. More interestingly, a scale‐up reaction system is established, achieving an NH 3 yield rate of 4.771 g h −1 and successfully converting the NH 3 in solution into solid NH 4 Cl. The aforementioned progress significantly enhances the facilitation of NH 3 electrosynthesis industrialization.