Maria Angelaki, Jill d’Erceville, D. James Donaldson, Christian George
{"title":"pH 值影响空气-水界面上 H2O2 的自发形成","authors":"Maria Angelaki, Jill d’Erceville, D. James Donaldson, Christian George","doi":"10.1021/jacs.4c07356","DOIUrl":null,"url":null,"abstract":"Recent studies have shown that the air–water interface of aqueous microdroplets is a source of OH radicals and hydrogen peroxide in the atmosphere. Several parameters such as droplet size, salt, and organic content have been suggested to play key roles in the formation of these oxidants. In this study, we focus on the effect of acidity on the spontaneous interfacial hydrogen peroxide formation of salt-containing droplets. Na<sub>2</sub>SO<sub>4</sub>, NaCl, and NaBr bulk solutions, at the range of pH 4 to 9.5, were nebulized, using ultra high-purity N<sub>2</sub>/O<sub>2</sub> (80%/20%), and H<sub>2</sub>O<sub>2</sub> was measured in the collected droplets. All of the experiments were performed in <i>T</i> = 292 ± 1 K and humidity levels of 90 ± 2%. For Na<sub>2</sub>SO<sub>4</sub> and NaCl, the H<sub>2</sub>O<sub>2</sub> concentration was increased by ∼40% under alkaline conditions, suggesting that OH<sup>–</sup> enriched environments promote its production. When CO<sub>2</sub> was added in the ultrapure air, H<sub>2</sub>O<sub>2</sub> was observed to be lower at higher pH. This suggests that dissolved CO<sub>2</sub> can initiate reactions with OH radicals and electrons, impacting the interfacial H<sub>2</sub>O<sub>2</sub> production. H<sub>2</sub>O<sub>2</sub> formation in NaBr droplets did not display any dependence on the pH or the bath gas, showing that secondary reactions occur at the interface in the presence of Br<sup>–</sup>, which acts as an efficient interfacial source of electrons.","PeriodicalId":49,"journal":{"name":"Journal of the American Chemical Society","volume":null,"pages":null},"PeriodicalIF":14.4000,"publicationDate":"2024-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"pH Affects the Spontaneous Formation of H2O2 at the Air–Water Interfaces\",\"authors\":\"Maria Angelaki, Jill d’Erceville, D. James Donaldson, Christian George\",\"doi\":\"10.1021/jacs.4c07356\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"Recent studies have shown that the air–water interface of aqueous microdroplets is a source of OH radicals and hydrogen peroxide in the atmosphere. Several parameters such as droplet size, salt, and organic content have been suggested to play key roles in the formation of these oxidants. In this study, we focus on the effect of acidity on the spontaneous interfacial hydrogen peroxide formation of salt-containing droplets. Na<sub>2</sub>SO<sub>4</sub>, NaCl, and NaBr bulk solutions, at the range of pH 4 to 9.5, were nebulized, using ultra high-purity N<sub>2</sub>/O<sub>2</sub> (80%/20%), and H<sub>2</sub>O<sub>2</sub> was measured in the collected droplets. All of the experiments were performed in <i>T</i> = 292 ± 1 K and humidity levels of 90 ± 2%. For Na<sub>2</sub>SO<sub>4</sub> and NaCl, the H<sub>2</sub>O<sub>2</sub> concentration was increased by ∼40% under alkaline conditions, suggesting that OH<sup>–</sup> enriched environments promote its production. When CO<sub>2</sub> was added in the ultrapure air, H<sub>2</sub>O<sub>2</sub> was observed to be lower at higher pH. This suggests that dissolved CO<sub>2</sub> can initiate reactions with OH radicals and electrons, impacting the interfacial H<sub>2</sub>O<sub>2</sub> production. H<sub>2</sub>O<sub>2</sub> formation in NaBr droplets did not display any dependence on the pH or the bath gas, showing that secondary reactions occur at the interface in the presence of Br<sup>–</sup>, which acts as an efficient interfacial source of electrons.\",\"PeriodicalId\":49,\"journal\":{\"name\":\"Journal of the American Chemical Society\",\"volume\":null,\"pages\":null},\"PeriodicalIF\":14.4000,\"publicationDate\":\"2024-09-16\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Journal of the American Chemical Society\",\"FirstCategoryId\":\"92\",\"ListUrlMain\":\"https://doi.org/10.1021/jacs.4c07356\",\"RegionNum\":1,\"RegionCategory\":\"化学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q1\",\"JCRName\":\"CHEMISTRY, MULTIDISCIPLINARY\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of the American Chemical Society","FirstCategoryId":"92","ListUrlMain":"https://doi.org/10.1021/jacs.4c07356","RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"CHEMISTRY, MULTIDISCIPLINARY","Score":null,"Total":0}
pH Affects the Spontaneous Formation of H2O2 at the Air–Water Interfaces
Recent studies have shown that the air–water interface of aqueous microdroplets is a source of OH radicals and hydrogen peroxide in the atmosphere. Several parameters such as droplet size, salt, and organic content have been suggested to play key roles in the formation of these oxidants. In this study, we focus on the effect of acidity on the spontaneous interfacial hydrogen peroxide formation of salt-containing droplets. Na2SO4, NaCl, and NaBr bulk solutions, at the range of pH 4 to 9.5, were nebulized, using ultra high-purity N2/O2 (80%/20%), and H2O2 was measured in the collected droplets. All of the experiments were performed in T = 292 ± 1 K and humidity levels of 90 ± 2%. For Na2SO4 and NaCl, the H2O2 concentration was increased by ∼40% under alkaline conditions, suggesting that OH– enriched environments promote its production. When CO2 was added in the ultrapure air, H2O2 was observed to be lower at higher pH. This suggests that dissolved CO2 can initiate reactions with OH radicals and electrons, impacting the interfacial H2O2 production. H2O2 formation in NaBr droplets did not display any dependence on the pH or the bath gas, showing that secondary reactions occur at the interface in the presence of Br–, which acts as an efficient interfacial source of electrons.
期刊介绍:
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