Photochemistry of Adsorbed Nitrate

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• 作者：Jennifer Schuttlefield ; Gayan Rubasinghege ; Mohamed El-Maazawi ; Jason Bone ; Vicki H. Grassian
• 刊名：Journal of the American Chemical Society
• 出版年：2008
• 出版时间：September 17, 2008
• 年：2008
• 卷：130
• 期：37
• 页码：12210-12211
• 全文大小：131K
• 年卷期：v.130,no.37(September 17, 2008)
• ISSN：1520-5126

文摘

In the atmosphere, gas-phase nitrogen oxides including nitric acid react with particle surfaces (e.g., mineral dust and sea salt aerosol) to yield adsorbed nitrate, yet little is known about the photochemistry of nitrate on the surface of these particles. In this study, nitrate adsorbed on alumina surfaces, a surrogate for mineral dust aerosol, is irradiated with broadband light (λ > 300 nm) in the absence and presence of coadsorbed water, at <1% and 45 ± 2% relative humidity (%RH), respectively, and molecular oxygen. Upon irradiation, the nitrate ion readily undergoes photolysis to yield nitrogen-containing gas-phase products, NO₂, NO, and N₂O. Although NO₂, NO, and N₂O form under the different conditions investigated, both coadsorbed water and molecular oxygen change the gas-phase product distribution, with NO being the major product under dry and humid conditions in the absence of molecular oxygen and NO₂ the major product in the presence of molecular oxygen. To the best of our knowledge, this is the first study to investigate the role of solvation by coadsorbed water in the photochemistry of adsorbates at solid interfaces and the roles that molecular oxygen, adsorbed water, and relative humidity may have in photochemical processes on aerosol surfaces that have the potential to alter the chemical balance of the atmosphere.