Göttingen 2025 – scientific programme
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P: Fachverband Plasmaphysik
P 21: Atmospheric Plasmas and their Applications V
P 21.2: Talk
Thursday, April 3, 2025, 14:15–14:30, ZHG006
controlled synthesis of NO and helium metastable measurement in atmospheric pressure RF plasma — •Siqi Yu, Steijn Vervloedt, Laura Chauvet, and Achim von Keudell — Ruhr-Universität Bochum, Bochum, Germany
Non-thermal plasma catalytic technology has promising potential to improve gas conversion efficiency. Our research focuses on nitrogen oxide synthesis, especially NO production, because of its broad range of applications in biological processes. NOx species are generated in a parallel-plate atmospheric pressure RF plasma from N2/O2 admixed to helium. The concentrations are measured by FTIR spectroscopy using a multi-pass cell. The results show that NO’s is further oxidized with increasing oxygen admixture and ozone generation. It can be controlled by increasing the surface temperature and by using a catalytic material that preferentially quenches O3. Helium metastable species act as an energy pool and play a crucial role during the discharge. Broadband absorption spectroscopy is used as an in-situ method to measure absolute densities of atomic He(23S1) and molecular He2(a3Σu+) metastable species. A 1D global model is developed to fit the experimental data and analyze metastable generation and destruction mechanisms. The helium metastable induced desorption of adsorbed water causes a decay of the metastable density along the plasma channel. Surface materials with a lower work function exhibit stronger secondary electron emission, affecting the local heating at the plasma boundary sheath. This increases the rate for He(23S1) and He2(a3Σu+) conversion.
Keywords: atmospheric pressure plasma; plasma catalysis; NO synthesis; broadband absorption; helium metastables