Yield validation of dinitrogen reduction reaction (N₂RR) catalysts with ¹⁵N isotope labeling experiments is frustrated by the high cost of ¹⁵N₂ and the frequent occurrence of ¹⁵NH₃ and ¹⁵NO_x impurities in commercial ¹⁵N₂ sources. Also, gas diffusion electrode (GDE) cell architectures are relevant to scaling N₂RR but underexplored and limited by ex situ product analysis methods. To overcome these obstacles, we develop and demonstrate a protocol for N₂RR catalyst testing using a scalable GDE cell architecture and specialized test station that facilitates in-line product analysis with multiturn time-of-flight mass spectrometry. This approach provides robust yield measurements through real-time monitoring of ¹⁵NH₃ with ultrahigh mass resolution. The ¹⁵N-containing impurities are also monitored, allowing their influence to be mitigated. A minimum detectable yield of 6 pmol·cm^–2·s^–1 (at 2.00 sccm and utilizing a 5 cm² electrode) for real-time ¹⁵NH₃ yield rate measurements is achieved while using a cost-effective amount of ¹⁵N₂ (<100 mL).

中文翻译：

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使用轨道多圈飞行时间质谱法进行实时 15NH3 产率定量的氮还原测试


由于 ¹⁵N₂ 的成本高，以及商业 ¹⁵_{N 2} 源中频繁出现 ¹⁵NH₃ 和 ¹⁵NO_x 杂质，因此使用 ¹⁵N 同位素标记实验对二氮还原反应 （N₂RR） 催化剂的产量验证受挫。此外，气体扩散电极 （GDE） 电池结构与缩放 N₂RR 相关，但未得到充分探索，并受到非原位产物分析方法的限制。为了克服这些障碍，我们开发并演示了一种 N₂RR 催化剂测试方案，该方案使用可扩展的 GDE 单元架构和专用测试站，便于使用多圈飞行时间质谱法进行在线产品分析。这种方法通过以超高质量分辨率实时监测 ¹⁵NH₃ 来提供稳定的产量测量。此外，还监测了 ¹⁵种含 N 的杂质，从而减轻了它们的影响。使用具有成本效益的 ¹⁵N₂ （<100 mL） 量，实时 ¹⁵NH₃ 产率测量的最低可检测产量为 6 pmol·cm^–2·s–1（在 2.00 sccm 下，使用 5 cm² 电极）。