Long-term continuous ammonia electrosynthesis

• 成果类型: Article
• 署名作者: Li, Shaofeng; Zhou, Yuanyuan; Fu, Xianbiao; Pedersen, Jakob B.; Saccoccio, Mattia; Andersen, Suzanne Z.; Enemark-Rasmussen, Kasper; Kempen, Paul J.; Damsgaard, Christian Danvad; Xu, Aoni; Sazinas, Rokas; Mygind, Jon Bjarke Valbaek; Deissler, Niklas H.; Kibsgaard, Jakob; Vesborg, Peter C. K.; Norskov, Jens K.; Chorkendorff, Ib
• 署名单位: Technical University of Denmark; Technical University of Denmark; Technical University of Denmark
• 刊物名称: Nature
• ISSN/ISSBN: 0028-3954
• DOI: 10.1038/s41586-024-07276-5
• 发表日期: 2024-05-02
• 关键词: ring-opening polymerization; electrochemical reduction; nitrogen reduction; tetrahydrofuran; electrolytes; EFFICIENCY; STABILITY; DYNAMICS; n2

摘要

Ammonia is crucial as a fertilizer and in the chemical industry and is considered to be a carbon-free fuel1. Ammonia electrosynthesis from nitrogen under ambient conditions offers an attractive alternative to the Haber-Bosch process2,3, and lithium-mediated nitrogen reduction represents a promising approach to continuous-flow ammonia electrosynthesis, coupling nitrogen reduction with hydrogen oxidation4. However, tetrahydrofuran, which is commonly used as a solvent, impedes long-term ammonia production owing to polymerization and volatility problems. Here we show that a chain-ether-based electrolyte enables long-term continuous ammonia synthesis. We find that a chain-ether-based solvent exhibits non-polymerization properties and a high boiling point (162 degrees C) and forms a compact solid-electrolyte interphase layer on the gas diffusion electrode, facilitating ammonia release in the gas phase and ensuring electrolyte stability. We demonstrate 300 h of continuous operation in a flow electrolyser with a 25 cm2 electrode at 1 bar pressure and room temperature, and achieve a current-to-ammonia efficiency of 64 +/- 1% with a gas-phase ammonia content of approximately 98%. Our results highlight the crucial role of the solvent in long-term continuous ammonia synthesis. Use of a chain-ether-based solvent instead of tetrahydrofuran for lithium-mediated nitrogen reduction enables long-term continuous ammonia electrosynthesis with high efficiency and improved gas-phase ammonia distribution.