A surface-stabilized ozonide triggers bromide oxidation at the aqueous solution-vapour interface

Abstract
Oxidation of bromide in aqueous environments initiates the formation of molecular halogen compounds, which is important for the global tropospheric ozone budget. In the aqueous bulk, oxidation of bromide by ozone involves a [Br•OOO-] complex as intermediate. Here we report liquid jet X-ray photoelectron spectroscopy measurements that provide direct experimental evidence for the ozonide and establish its propensity for the solution-vapour interface. Theoretical calculations support these findings, showing that water stabilizes the ozonide and lowers the energy of the transition state at neutral pH. Kinetic experiments confirm the dominance of the heterogeneous oxidation route established by this precursor at low, atmospherically relevant ozone concentrations. Taken together, our results provide a strong case of different reaction kinetics and mechanisms of reactions occurring at the aqueous phase-vapour interface compared with the bulk aqueous phase.

Citation
Artiglia, L., Edebeli, J., Orlando, F., Chen, S., Lee, M.-T., Corral Arroyo, P., … Ammann, M. (2017). A surface-stabilized ozonide triggers bromide oxidation at the aqueous solution-vapour interface. Nature Communications, 8(1). doi:10.1038/s41467-017-00823-x

Acknowledgements
For computer time, this research used the resources of the Supercomputing Laboratory at King Abdullah University of Science and Technology (KAUST) in Thuwal, Saudi Arabia. The engineering work and technical support by Mario Birrer is greatly acknowledged. J.E. acknowledges the Swiss National Science Foundation (SNF), grant 155999. M.A., F.O. and S.C. acknowledge funding by the Swiss National Science Foundation (grants no 149492 and 169176). We thank Michel Rossi for providing the ozone generator.

Publisher
Springer Science and Business Media LLC

Journal
Nature Communications

DOI
10.1038/s41467-017-00823-x

PubMed ID
28951540

PubMed Central ID
PMC5615067

Additional Links
http://www.nature.com/articles/s41467-017-00823-x

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