丹麦工业大学Jens K. Norskov和Ib Chorkendorff小组在合成氨研究中取得进展。他们发现，添加氧气可增强锂介导的氨合成。相关论文于2021年12月24日发表于国际顶尖学术期刊《科学》杂志上。

该研究团队证明，之前被认为是阻碍反应的氧气，当少量添加到反应环境中时，实际上大大提高了锂介导氮还原的法拉第效率和的稳定性。凭借这一有违直觉的发现，研究团队在20 bar氮气中氧浓度为0.6 ~ 0.8 mol%时，达到了创纪录的78.0 ± 1.3%的法拉第效率。实验X射线分析和理论微动力学建模揭示了其潜在的机理。

据介绍，由于大气中二氧化碳浓度令人担忧地增加，有必要将化石燃料驱动的化学过程——例如Haber-Bosch氨合成——电气化。锂介导的电化学氮还原已初步显示出潜力，但仍缺乏足够的法拉第效率和氨生成速率来实现工业化。

附：英文原文

Title: Enhancement of lithium-mediated ammonia synthesis by addition of oxygen

Author: Katja Li, Suzanne Z. Andersen, Michael J. Statt, Mattia Saccoccio, Vanessa J. Bukas, Kevin Krempl, Rokas Sainas, Jakob B. Pedersen, Vahid Shadravan, Yuanyuan Zhou, Debasish Chakraborty, Jakob Kibsgaard, Peter C. K. Vesborg, Jens K. Nrskov, Ib Chorkendorff

Issue&Volume: 2021-12-24

Abstract: Owing to the worrying increase in carbon dioxide concentrations in the atmosphere, there is a need to electrify fossil-fuel–powered chemical processes such as the Haber-Bosch ammonia synthesis. Lithium-mediated electrochemical nitrogen reduction has shown preliminary promise but still lacks sufficient faradaic efficiency and ammonia formation rate to be industrially relevant. Here, we show that oxygen, previously believed to hinder the reaction, actually greatly improves the faradaic efficiency and stability of the lithium-mediated nitrogen reduction when added to the reaction atmosphere in small amounts. With this counterintuitive discovery, we reach record high faradaic efficiencies of up to 78.0 ± 1.3% at 0.6 to 0.8 mole % oxygen in 20 bar of nitrogen. Experimental x-ray analysis and theoretical microkinetic modeling shed light on the underlying mechanism.

DOI: abl4300

Source: https://www.science.org/doi/10.1126/science.abl4300