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Low-pressure chemical and photochemical reactions of oxides of nitrogen on alumina taken as a model substance for mineral dust in relation to air pollution |
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| Authors: | A.A. Lisachenko A.O. Klimovskii R.V. Mikhailov B.N. Shelimov M. Che |
| Affiliation: | aFock Institute of Physics, St.-Petersburg State University, St.-Petersburg, Russia bZelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Moscow, Russia cUniversité Pierre et Marie Curie, Laboratoire de Réactivité de Surface, UMR 7609—CNRS, Paris, France |
| Abstract: | The interaction of γ-Al2O3, taken as a model substance of tropospheric mineral dust, with N2O, NO and NO2 has been studied using kinetic and temperature-programmed desorption (TPD) mass-spectrometry in presence and absence of UV irradiation. At low surface coverages (<0.001 ML), adsorption of N2O and NO2 is accompanied by dissociation and chemiluminescence, whereas adsorption of NO does not lead to appreciable dissociation. Upon UV irradiation of Al2O3 in a flow of N2O, photoinduced decomposition and desorption of N2O take place, whereas in a flow of NO, only photoinduced desorption is observed. Dark dissociative adsorption of N2O and NO and photoinduced N2O dissociation apparently occur by a mechanism involving electron capture from surface F- and F+-centers. Photoinduced desorption of N2O and NO may be associated with decomposition of complexes of these molecules with Lewis acid sites, V-centers or OH-groups. TPD of N2O and NO proceeds predominantly without decomposition, while NO2 partially decomposes to NO and O2. |
| Keywords: | Air pollution Mineral dust Alumina Nitrogen oxide UV irradiation Adsorption Dissociation |
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