The formation of atomic oxygen and hydrogen in atmospheric pressure plasmas containing humidity : picosecond two-photon absorption laser induced fluorescence and numerical simulations
| Autor: | Jerome Bredin, Deborah O'Connell, Timo Gans, James Dedrick, Sandra Schröter, Erik Wagenaars, Andrew Gibson, Andrew West, Kari Niemi |
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| Jazyk: | angličtina |
| Rok vydání: | 2020 |
| Předmět: |
010302 applied physics
Materials science Hydrogen Atmospheric pressure Analytical chemistry chemistry.chemical_element FOS: Physical sciences Condensed Matter Physics 01 natural sciences 7. Clean energy Physics - Plasma Physics 010305 fluids & plasmas 3. Good health Plasma Physics (physics.plasm-ph) chemistry 13. Climate action Excited state Picosecond 0103 physical sciences Laser-induced fluorescence Absorption (electromagnetic radiation) Helium Water vapor |
| ISSN: | 0963-0252 |
| Popis: | Atmospheric pressure plasmas are effective sources for reactive species, making them applicable for industrial and biomedical applications. We quantify ground-state densities of key species, atomic oxygen (O) and hydrogen (H), produced from admixtures of water vapour (up to 0.5%) to the helium feed gas in a radio-frequency-driven plasma at atmospheric pressure. Absolute density measurements, using two-photon absorption laser induced fluorescence, require accurate effective excited state lifetimes. For atmospheric pressure plasmas, picosecond resolution is needed due to the rapid collisional de-excitation of excited states. These absolute O and H density measurements, at the nozzle of the plasma jet, are used to benchmark a plug-flow, 0D chemical kinetics model, for varying humidity content, to further investigate the main formation pathways of O and H. It is found that impurities can play a crucial role for the production of O at small molecular admixtures. Hence, for controllable reactive species production, purposely admixed molecules to the feed gas is recommended, as opposed to relying on ambient molecules. The controlled humidity content was also identified as an effective tailoring mechanism for the O/H ratio. 35 pages, 14 figures |
| Databáze: | OpenAIRE |
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