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

Conversion of air and water into valuable chemicals of ammonia (NH3) by plasma activation and electrochemical reduction is a promising approach to achieve zero carbon-emission synthesis of NH3. 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 NH3 partial current density (1559 mA cm-2), superior NH3 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 NH3 to the knowledge. The introduction of W makes the Co atom surface electron deficient, which can enhance the adsorption of NOx- and mitigate the excessive bonding of hydroxyl radicals (OH*) generated during nitrite (NO2*) hydrogenation, thereby reducing the energy barrier of the potential-determining step. More interestingly, a scale-up reaction system is established, achieving an NH3 yield rate of 4.771 g h-1 and successfully converting the NH3 in solution into solid NH4Cl. The aforementioned progress significantly enhances the facilitation of NH3 electrosynthesis industrialization. A self-supported CoW/CF catalyst is developed to efficiently synthesize NH3. Through the combination of plasma and electrocatalysis, the catalyst shows an impressive NH3 yield rate of 164.3 mg h-1 cm-2 and an excellent FE of 98.2%. Additionally, a gram-level NH3 yield rate of 4.771 g h-1 can be achieved and effectively converted into a multifunctional solid of NH4Cl.image