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The HO4H → O3 + H2O reaction catalysed by acidic, neutral and basic catalysts in the troposphere.
- Source :
- Molecular Physics; Jun2020, Vol. 118 Issue 12, p1-11, 11p
- Publication Year :
- 2020
-
Abstract
- A detailed effects of catalyst X (X = H<subscript>2</subscript>O, (H<subscript>2</subscript>O)<subscript>2</subscript>, NH<subscript>3</subscript>, NH<subscript>3</subscript>···H<subscript>2</subscript>O, H<subscript>2</subscript>O···NH<subscript>3</subscript>, HCOOH and H<subscript>2</subscript>SO<subscript>4</subscript>) on the HO<subscript>4</subscript>H → O<subscript>3</subscript> + H<subscript>2</subscript>O reaction have been investigated by using quantum chemical calculations and canonical vibrational transition state theory with small curvature tunnelling. The calculated results show that (H<subscript>2</subscript>O)<subscript>2</subscript>-catalysed reactions much faster than H<subscript>2</subscript>O-catalysed one because of the former bimolecular rate constant larger by 2.6–25.9 times than that of the latter one. In addition, the basic H<subscript>2</subscript>O···NH<subscript>3</subscript> catalyst was found to be a better than the neutral catalyst of (H<subscript>2</subscript>O)<subscript>2</subscript>. However it is marginally less efficient than the acidic catalysts of HCOOH, and H<subscript>2</subscript>SO<subscript>4</subscript>. The effective rate constant (k'<subscript>t</subscript>) in the presence of catalyst X have been assessed. It was found from k'<subscript>t</subscript> that H<subscript>2</subscript>O (at 100% RH) completely dominates over all other catalysts within the temperature range of 280–320 K at 0 km altitude. However, compared with the rate constant of HO<subscript>4</subscript>H → H<subscript>2</subscript>O + O<subscript>3</subscript> reaction, the k<subscript>eff</subscript> values for H<subscript>2</subscript>O catalysed reaction are smaller by 1–2 orders of magnitude, indicating that the catalytic effect of H<subscript>2</subscript>O makes a negligible contribution to the gas phase reaction of HO<subscript>4</subscript>H → O<subscript>3</subscript> + H<subscript>2</subscript>O. Highlights A detailed effects of catalyst of H<subscript>2</subscript>O, (H<subscript>2</subscript>O)<subscript>2</subscript>, NH<subscript>3</subscript>, NH<subscript>3</subscript>···H<subscript>2</subscript>O, H<subscript>2</subscript>O···NH<subscript>3</subscript>, HCOOH and H<subscript>2</subscript>SO<subscript>4</subscript> on the HO<subscript>4</subscript>H → O<subscript>3</subscript> + H<subscript>2</subscript>O reaction has been performed. From energetic viewpoint, H<subscript>2</subscript>SO<subscript>4</subscript> exerts the strongest catalytic role in HO<subscript>4</subscript>H → O<subscript>3</subscript> + H<subscript>2</subscript>O reaction as compared with the other catalysts. At 0 km altitude H<subscript>2</subscript>O (at 100% RH) completely dominates over all other catalysts within the temperature range of 280–320 K. HO<subscript>4</subscript>H → H<subscript>2</subscript>O + O<subscript>3</subscript> reaction with H<subscript>2</subscript>O cannot be compete with the reaction without catalyst, due to the fact that the effective rate constants in the presence of H<subscript>2</subscript>O are smaller. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 00268976
- Volume :
- 118
- Issue :
- 12
- Database :
- Complementary Index
- Journal :
- Molecular Physics
- Publication Type :
- Academic Journal
- Accession number :
- 144691412
- Full Text :
- https://doi.org/10.1080/00268976.2019.1673912