Self‐Supported Catalytic Electrode of CoW/Co‐Foam Achieves Efficient Ammonia Synthesis at Ampere‐Level Current Density
Kang Xia, Xuejing Yang, Zhe Meng, X. F. Sun, Miaomiao Shi, Hong‐Rui Li, Rui Gao, Bo Bi, Dongxue Liu, Jun‐Min Yan, Qing Jiang
Abstract
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.