Wang Yanjie, Luo Jin, Fang Ye-Guang, Nan Zi-Ang, Cui Xi, Chen Ting, Zeng Xiangbiao, Wang Xiaofei, Song Xianmeng, Zhao Jiawei, Li Weixin, Zeng Chen, Chen Daliang, Zhu Chongqin, Wei Zhenwei, Tian Zhong-Qun, Fan Feng Ru
State Key Laboratory of Physical Chemistry of Solid Surfaces, iChEM, College of Chemistry and Chemical Engineering, Innovation Laboratory for Sciences and Technologies of Energy Materials of Fujian Province (IKKEM), Xiamen University, Xiamen 361005, China.
College of Chemistry, Key Laboratory of Theoretical & Computational Photochemistry of Ministry of Education, Beijing Normal University, Beijing 100875, China.
J Am Chem Soc. 2025 Jan 22;147(3):2756-2765. doi: 10.1021/jacs.4c15514. Epub 2025 Jan 11.
Nitrogen fixation is essential for the sustainable development of both human society and the environment. Due to the chemical inertness of the N≡N bond, the traditional Haber-Bosch process operates under extreme conditions, making nitrogen fixation under ambient conditions highly desirable but challenging. In this study, we present an ultrasonic atomizing microdroplet method that achieves nitrogen fixation using water and air under ambient conditions in a rationally designed sealed device, without the need for any catalyst. The total nitrogen fixation rate achieved is 6.99 μmol/h, yielding ammonium as the reduction product and nitrite and nitrate as the oxidation products, with hydrogen peroxide produced as a byproduct at a rate of 4.29 μmol/h. Using electron paramagnetic resonance (EPR) spectroscopy, we captured reactive species, including hydrogen, hydroxyl, singlet oxygen, superoxide anion, and NO radicals. In conjunction with in situ mass spectrometry (MS) and isotope labeling, we confirmed the presence of nitrogen-containing intermediates, such as HN═NOH, HN-N(OH), HNO, and NHOH. Supported by these findings and theoretical calculations, we propose a radical-mediated nitrogen disproportionation mechanism. Simulations of naturally occurring condensed microdroplets also demonstrated nitrogen redox fixation. This microdroplet-based method not only offers a potential pathway for nitrogen fixation in practical applications and sustainable development but also deepens our understanding of the natural nitrogen cycle.
固氮对于人类社会和环境的可持续发展至关重要。由于N≡N键的化学惰性，传统的哈伯-博施法在极端条件下运行，使得在环境条件下固氮极具吸引力但也具有挑战性。在本研究中，我们提出了一种超声雾化微滴法，该方法在合理设计的密封装置中，在环境条件下使用水和空气实现固氮，无需任何催化剂。实现的总固氮速率为6.99 μmol/h，还原产物为铵，氧化产物为亚硝酸盐和硝酸盐，副产物过氧化氢的生成速率为4.29 μmol/h。使用电子顺磁共振（EPR）光谱，我们捕获了包括氢、羟基、单线态氧、超氧阴离子和NO自由基在内的活性物种。结合原位质谱（MS）和同位素标记，我们证实了含氮中间体的存在，如HN═NOH、HN-N(OH)、HNO和NHOH。在这些发现和理论计算的支持下，我们提出了一种自由基介导的氮歧化机制。对天然存在的凝聚微滴的模拟也证明了氮的氧化还原固定。这种基于微滴的方法不仅为实际应用和可持续发展中的固氮提供了一条潜在途径，也加深了我们对自然氮循环的理解。
