The effect of cations on NO2 production from the photolysis of aqueous thin water films of nitrate salts.
The effect of cations on NO2 production from the photolysis of aqueous thin water films of nitrate salts.
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阳离子对硝酸盐水薄膜光解产生 NO2 的影响。
DOI：
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发表时间：
2015
期刊：
影响因子：
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通讯作者：
B. Finlayson‐Pitts
中科院分区：
文献类型：
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作者：
N. K. Richards;C. Anderson;C. Anastasio;B. Finlayson‐Pitts
硝酸盐离子在大量水溶液中的光化学反应是众所周知的，但最近的证据表明，硝酸盐的光解可能在空气-水界面更有效。这种表面增强是否以及如何被不同阳离子的存在所改变尚不清楚。在本研究中，在聚四氟乙烯腔壁上沉积了不同阳离子的硝酸盐水薄膜，并在298 K下用311 nm光照射。通过雾化0.5 M硝酸盐水溶液生成膜，并随时间监测气相NO2的生成。根据观察到的NO2生成速率（R(NO2)），硝酸盐可分为三类：(1)易于生成NO2的RbNO3和KNO3 (R(NO2) bb0 3 ppb min(-1)),(2)生成NO2较慢的Ca(NO3)2 (R(NO2) < 1 ppb min(-1))，以及(3)介于其他两类之间的Mg(NO3)2和NaNO3。硝酸盐溶液紫外可见光谱的差异和体相光解研究的结果都不能解释这三组之间NO2生成速率的差异。这些实验结果，结合先前分子动力学模拟和振动和频率生成研究的一些见解，表明阳离子可能影响界面区域硝酸盐离子的浓度，从而直接影响硝酸盐离子的有效量子产率。
The photochemistry of nitrate ions in bulk aqueous solution is well known, yet recent evidence suggests that the photolysis of nitrate may be more efficient at the air-water interface. Whether and how this surface enhancement is altered by the presence of different cations is not known. In the present studies, thin aqueous films of nitrate salts with different cations were deposited on the walls of a Teflon chamber and irradiated with 311 nm light at 298 K. The films were generated by nebulizing aqueous 0.5 M solutions of the nitrate salts and the generation of gas-phase NO2 was monitored with time. The nitrate salts fall into three groups based on their observed rate of NO2 formation (R(NO2)): (1) RbNO3 and KNO3, which readily produce NO2 (R(NO2) > 3 ppb min(-1)), (2) Ca(NO3)2, which produces NO2 more slowly (R(NO2) < 1 ppb min(-1)), and (3) Mg(NO3)2 and NaNO3, which lie between the other two groups. Neither differences in the UV-visible spectra of the nitrate salt solutions nor the results of bulk-phase photolysis studies could explain the differences in the rates of NO2 production between these three groups. These experimental results, combined with some insights from previous molecular dynamic simulations and vibrational sum frequency generation studies, show that cations may impact the concentration of nitrate ions in the interface region, thereby directly impacting the effective quantum yields for nitrate ions.
影响因子：
15
作者：
Hribar, B;Southall, NT;Dill, KA
通讯作者：
Dill, KA