Non-aqueous gas diffusion electrodes for rapid ammonia synthesis from nitrogen and water-splitting-derived hydrogen
Non-aqueous gas diffusion electrodes for rapid ammonia synthesis from nitrogen and water-splitting-derived hydrogen
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DOI：
10.1038/s41929-020-0455-8
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发表时间：
2020-05-04
期刊：
影响因子：
37.8
通讯作者：
Manthiram, Karthish
中科院分区：
文献类型：
--
作者：
Lazouski, Nikifar;Chung, Minju;Manthiram, Karthish
在非水溶剂中的电化学转化对于合成和储能应用是非常重要的。非极性气体反应物，如氮气和氢气在非水溶剂中的使用受到其低溶解度和传输速度慢的限制。传统的气体扩散电极通过促进电极附近有效的气液接触，改善了气体在电解液中的传输。它们在非水溶剂中的使用受到了液体和碳纤维载体之间不存在疏水斥力的阻碍。在此，我们报告了一种克服四氢呋喃运输限制的方法，该方法使用不锈钢布为基础的载体，用于氨合成和氢氧化。用锂介电的方法获得了8.8+/-1.4 mA·cm(-2)的氨分电流密度和35+/-6%的法拉第效率。在两种非水溶剂中获得了高达25 mA cm(-2)的氢氧化电流密度，其法拉第效率接近统一。然后，该方法被应用于从氮气和水裂解衍生的氢气中生产氨。
Electrochemical transformations in non-aqueous solvents are important for synthetic and energy storage applications. Use of non-polar gaseous reactants such as nitrogen and hydrogen in non-aqueous solvents is limited by their low solubility and slow transport. Conventional gas diffusion electrodes improve the transport of gaseous species in aqueous electrolytes by facilitating efficient gas-liquid contacting in the vicinity of the electrode. Their use with non-aqueous solvents is hampered by the absence of hydrophobic repulsion between the liquid phase and carbon fibre support. Herein we report a method to overcome transport limitations in tetrahydrofuran using a stainless steel cloth-based support for ammonia synthesis paired with hydrogen oxidation. An ammonia partial current density of 8.8 +/- 1.4 mA cm(-2) and a Faradaic efficiency of 35 +/- 6% are obtained using a lithium-mediated approach. Hydrogen oxidation current densities of up to 25 mA cm(-2) are obtained in two non-aqueous solvents with near-unity Faradaic efficiency. The approach is then applied to produce ammonia from nitrogen and water-splitting-derived hydrogen.