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Matrix effect on surface-catalyzed photolysis of nitric acid
Photolysis rate constant of HNO on the surface (HNO ) has been found to be enhanced by 1-4 orders of magnitude from that of gaseous HNO , with HONO and NO as the main products. Such Re-NOx-ification pathway extends the apparent lifetime of reactive nitrogen species and modifies the atmospheric oxida...
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Published in: | Scientific reports 2019-03, Vol.9 (1), p.4351, Article 4351 |
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Main Authors: | , , , |
Format: | Article |
Language: | English |
Subjects: | |
Citations: | Items that this one cites Items that cite this one |
Online Access: | Get full text |
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Summary: | Photolysis rate constant of HNO
on the surface (HNO
) has been found to be enhanced by 1-4 orders of magnitude from that of gaseous HNO
, with HONO and NO
as the main products. Such Re-NOx-ification pathway extends the apparent lifetime of reactive nitrogen species and modifies the atmospheric oxidative capacity along its long-rang transport. Despite of its importance, the detailed kinetics and mechanisms of HNO
photolysis are still not clear. Surface film of HNO
and organic compounds is ubiquitous in the environment and imposes matrix effect on HNO
photolysis. Here we studied photolysis of HNO
on Pyrex glass in a photochemical flow reactor over a wide range of HNO
surface density (D
) with or without the presence of model organic compounds. The photolysis rate constant of HNO
varied with D
and surface-catalysis mechanism was proposed. Organic compounds further enhance the photolysis rate constant by up to one order of magnitude via both photosensitization and H-donating reaction. The H-donating reaction enhances as well the secondary HONO yield from reaction between the primary product NO
and adjacent H-donor, and thus increases the HONO/NO
production ratio. Finally, detailed mechanisms involving surface-catalyisis, photosensitization and H-donating reactions was integrated. |
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ISSN: | 2045-2322 2045-2322 |
DOI: | 10.1038/s41598-018-37973-x |