Activities per year
Abstract
Atmospheric pressure plasmas are sources of biologically active oxygen and nitrogen species, which makes them potentially suitable for the use as biomedical devices. Here, experiments and simulations are combined to investigate the formation of the key reactive oxygen species, atomic oxygen (O) and hydroxyl radicals (OH), in a radio-frequency driven atmospheric pressure plasma jet operated in humidified helium. Vacuum ultra-violet high-resolution Fourier-transform absorption spectroscopy and ultra-violet broad-band absorption spectroscopy are used to measure absolute densities of O and OH. These densities increase with increasing H 2 O content in the feed gas, and approach saturation values at higher admixtures on the order of 3 × 10 14 cm −3 for OH and 3 × 10 13 cm −3 for O. Experimental results are used to benchmark densities obtained from zero-dimensional plasma chemical kinetics simulations, which reveal the dominant formation pathways. At low humidity content, O is formed from OH + by proton transfer to H 2 O, which also initiates the formation of large cluster ions. At higher humidity content, O is created by reactions between OH radicals, and lost by recombination with OH. OH is produced mainly from H 2 O + by proton transfer to H 2 O and by electron impact dissociation of H 2 O. It is lost by reactions with other OH molecules to form either H 2 O + O or H 2 O 2 . Formation pathways change as a function of humidity content and position in the plasma channel. The understanding of the chemical kinetics of O and OH gained in this work will help in the development of plasma tailoring strategies to optimise their densities in applications.
Original language | English |
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Pages (from-to) | 24263-24286 |
Number of pages | 24 |
Journal | Physical Chemistry Chemical Physics |
Volume | 20 |
Issue number | 37 |
Early online date | 13 Sept 2018 |
DOIs | |
Publication status | Published - 26 Sept 2018 |
Bibliographical note
Funding Information:The authors would like to thank Dr Daniel Schröder, Dr Mickaël Foucher and Richard Armitage for helping with experimental setups and taking measurements. We are grateful to Denis Joyeux for the development of the FTS and for his help during the synchrotron campaign. This work was financially supported by the UK EPSRC (EP/K018388/1 & EP/H003797/2), and the York-Paris Low Temperature Plasma Collaborative Research Centre. Additionally, this work was performed within the LABEX Plas@par project and received financial state aid, managed by the Agence National de la Recherche as part of the programme ‘‘Investissements d’avenir’’ (ANR-11-IDEX-0004-02). Apiwat Wijaikhum acknowledges financial support from the Development and Promotion of Science and Technology Talents Project (DPST), Royal Government of Thailand scholarship, and ThEP Center through project ‘Cold atmospheric pressure plasma against drug resistant microorganisms for wound healing’ (ThEP-60-PHM-CMU1). Andrew R. Gibson acknowledges funding from the Wellcome Trust [ref. 204829] through the Centre for Future Health (CFH) at the University of York. Helen Davies acknowledges financial support from the Wellcome Trust 4 year PhD programme [WT095024MA]: ‘‘Combating Infectious Disease: Computation Approaches in Translational Science’’. James Dedrick acknowledges financial support from an Australian Government Endeavour Research Fellowship. The participation of Mark J. Kushner was supported by the US Department of Energy (DE-SC0001319 and DE-SC0014132) and US National Science Foundation (PHY-1519117).
Publisher Copyright:
© the Owner Societies.
Copyright:
Copyright 2018 Elsevier B.V., All rights reserved.
Profiles
Activities
- 2 Invited talk
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59th Annual Meeting of the APS Division of Plasma Physics
Erik Wagenaars (Invited speaker)
23 Oct 2017 → 27 Oct 2017Activity: Talk or presentation › Invited talk
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International Conference on Phenomena in Ionized Gases 2017
Erik Wagenaars (Invited speaker)
9 Jul 2017 → 14 Jul 2017Activity: Talk or presentation › Invited talk
Datasets
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Chemical kinetics in an atmospheric pressure helium plasma containing humidity - data sets
Schröter, S. (Data Manager), Wijaikhum, A. (Contributor), Gibson, A. R. (Contributor), West, A. (Contributor), Davies, H. (Contributor), Minesi, N. (Contributor), Dedrick, J. P. (Contributor), Wagenaars, E. (Contributor), de Oliveira, N. (Contributor), Nahon, L. (Contributor), Kushner, M. J. (Contributor), Booth, J. (Contributor), Niemi, K. (Contributor), Gans, T. (Contributor) & O'Connell, D. (Creator), University of York, 2018
DOI: 10.15124/1a186859-ad12-4e33-bf17-ccfcbad48ba0
Dataset