Realizing Unconventional Tandem Nitrate Reduction for Efficient Ammonia Electrosynthesis Enabled by Co, Fe Dual‐Site Conjugated Metal Organic Frameworks
Shengji Tian, Runjie Wu, Hengjie Liu, Chunshuang Yan, Zeming Qi, Pin Song, Wen‐Jie Chen, Li Song, Zheng Wang, Chade Lv
Abstract
Abstract The electrochemical nitrate‐to‐ammonia reduction reaction (NO 3 RR) offers a sustainable route for carbon‐neutral chemical synthesis, while the intricate multi‐electron/proton transfer processes and unstable intermediates pose significant challenges in attaining high selectivity and efficiency. This study demonstrates a Co, Fe bimetallic conjugated metal organic frameworks (CoFe‐cMOFs) that enable efficient NO 3 RR via an unconventional [6 + 2] electron‐transfer tandem pathway. Unlike the traditional [2 + 6] tandem pathway, the Fe sites predominantly reduce NO 3− to *NH 2 OH intermediate, which subsequently spills over onto the Co sites for further protonation. This unconventional tandem pathway effectively avoids the release of NO 2− and guarantees selective NH 3 production. The CoFe‐cMOFs achieve 94.3% NH 3 ‐producing Faradaic efficiency with a yield rate of 14.1 mg h −1 cm −2 in neutral electrolyte. The Zn‐NO 3 − battery prototype incorporating CoFe‐cMOFs exhibits 3.6 mW cm −2 peak power density with stable NH 3 production. This work proposes a mechanistic breakthrough in tandem pathway regulation for selective electrochemical ammonia synthesis.