Simultaneous Reduction and Oxidation of NO2 on Water Microdroplets Provides Previously Unknown Pathways to the Formation of HONO and HNO3

IF 15.6 1区化学 Q1 CHEMISTRY, MULTIDISCIPLINARY

Journal of the American Chemical Society Pub Date : 2025-10-09 DOI:10.1021/jacs.5c12051

Huan Chen, Xu Yuan, Jianze Zhang, Xiangyu Chen, Joseph S. Francisco, Yifan Meng, Xinxing Zhang

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Abstract

HONO and HNO₃ are important atmospheric species, yet their formation pathways in the atmosphere remain uncertain. In this study, we report the simultaneous formation of HONO and HNO₃ at the air–water interface of water microdroplets in the presence of trace amounts of NO₂. Water microdroplets were generated either in ambient air or in a glovebox where the gas content could be precisely controlled. The products generated by the microdroplets and surrounding gas were directly analyzed with mass spectrometers. Our results indicated that NO₂ gas could be reduced by an electron to form NO₂^–, which was further protonated to yield HONO, or could be oxidized by a hydroxyl radical (·OH) to form HNO₃. Electrons and ·OH were produced by a strong electric field that facilitated OH^– dissociation at the air–water interface of the microdroplets. Tandem mass spectrometry, isotope labeling, and chemical ionization methods confirmed the formation of neutral HONO and HNO₃. Our results provide a previously unknown pathway for the formation of HONO and HNO₃ in the troposphere.

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微水滴上NO2的同时还原和氧化为HONO和HNO3的形成提供了以前未知的途径

HONO和HNO3是重要的大气物质，但它们在大气中的形成途径仍不确定。在本研究中，我们报道了在微量NO2存在的情况下，水微滴的空气-水界面同时形成HONO和HNO3。水微滴要么在环境空气中产生，要么在可以精确控制气体含量的手套箱中产生。用质谱仪直接分析了微滴和周围气体产生的产物。结果表明，NO2气体可以被电子还原生成NO2 -， NO2 -被进一步质子化生成HONO，也可以被羟基自由基（·OH）氧化生成HNO3。在强电场作用下，微滴的空气-水界面处OH -解离产生电子和·OH。串联质谱、同位素标记和化学电离方法证实了中性HONO和HNO3的形成。我们的研究结果为对流层中HONO和HNO3的形成提供了一个以前未知的途径。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Journal of the American Chemical Society 化学-化学综合

CiteScore

24.40

自引率

6.00%

发文量

2398

审稿时长

1.6 months

期刊介绍： The flagship journal of the American Chemical Society, known as the Journal of the American Chemical Society (JACS), has been a prestigious publication since its establishment in 1879. It holds a preeminent position in the field of chemistry and related interdisciplinary sciences. JACS is committed to disseminating cutting-edge research papers, covering a wide range of topics, and encompasses approximately 19,000 pages of Articles, Communications, and Perspectives annually. With a weekly publication frequency, JACS plays a vital role in advancing the field of chemistry by providing essential research.