Mechanistic insight into the competition between interfacial and bulk reactions in microdroplets through N2O5 ammonolysis and hydrolysis

• Published in: Nature communications Vol. 15; no. 1; pp. 2347 - 11
• Main Authors: Fang, Ye-Guang, Tang, Bo, Yuan, Chang, Wan, Zhengyi, Zhao, Lei, Zhu, Shuang, Francisco, Joseph S., Zhu, Chongqin, Fang, Wei-Hai
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 15.03.2024; Nature Publishing Group; Nature Portfolio
• Subjects: 119/118; 639/638/440/950; 639/638/563; 704/172/169/824; Aerosols; Ammonia; Ammonolysis; Atmospheric aerosols; Computational chemistry; Computer applications; Humanities and Social Sciences; Hydrolysis; multidisciplinary; Quantum chemistry; Science; Science (multidisciplinary); Strategy; Troposphere; Water
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-024-46674-1

Reactive uptake of dinitrogen pentaoxide (N 2 O 5 ) into aqueous aerosols is a major loss channel for NO x in the troposphere; however, a quantitative understanding of the uptake mechanism is lacking. Herein, a computational chemistry strategy is developed employing high-level quantum chemical methods; the method offers detailed molecular insight into the hydrolysis and ammonolysis mechanisms of N 2 O 5 in microdroplets. Specifically, our calculations estimate the bulk and interfacial hydrolysis rates to be (2.3 ± 1.6) × 10 −3 and (6.3 ± 4.2) × 10 −7 ns −1 , respectively, and ammonolysis competes with hydrolysis at NH 3 concentrations above 1.9 × 10 −4  mol L −1 . The slow interfacial hydrolysis rate suggests that interfacial processes have negligible effect on the hydrolysis of N 2 O 5 in liquid water. In contrast, N 2 O 5 ammonolysis in liquid water is dominated by interfacial processes due to the high interfacial ammonolysis rate. Our findings and strategy are applicable to high-chemical complexity microdroplets. The authors report a computational strategy to simulate the hydrolysis and ammonolysis of N 2 O 5 in aerosols using high-level quantum chemical methods. The computational results reveal a complete picture of the reactive uptake of N 2 O 5 by atmospheric aerosols with or without NH 3 .