A3: Excitation transfer between molecules in transient atmospheric pressure plasmas and its impact on plasma chemistry

Principal Investigators: A. von Keudell, D. Reiser

Team

von Keudell, Achim (Principal Investigator)

Chauvet, Laura (PostDoc)

Reiser, Dirk (Principal Investigator)

Vervloedt, Steijn (PhD)

Yu, Siqi (PhD)

Seferoglu, Fatma-Nur (PhD)

Description

The internal excitation of molecules and the non-equilibrium population of the degrees of freedom of molecules in a plasma is at the core of plasma chemistry. For example, vibrational excitation lowers activation barriers for electron induced dissociation reactions and determines thereby the energy and conversion efficiency of a plasma chemical process. Metastable states store electronic excitation, which can be transferred to molecules to trigger dissociation. This project aims at a fundamental understanding of the transfer of this excitation depending on the plasma (leading to a specific electron energy distribution function) and the plasma mixture defining the collision partners and thereby the various quenching routes and on the different reactive surfaces. This is evaluated by using Fourier transform infrared absorption (FTIR) spectroscopy for molecules with strong dipole moments such as CO2, CH4, CO, and H2O for lower lying excitation states and threshold ionisation (TI) molecular beam mass spectrometry (MBMS) for higher metastable excitation states. This is combined with an in-situ analysis of the catalytic surfaces using infrared reflection absorption techniques (IRRAS) and spectroscopic ellipsometry (SE). A multi diagnostics set-up will be developed to integrate the various plasma excitation schemes of the CRC 1316 and the different catalytic active surfaces.

Publications

• Oxygen removal from a hydrocarbon containing gas stream by plasma catalysis
  T. Urbanietz, C. Stewig, M. Böke, A. von Keudell
  Plasma Chem Plasma Process 41, 619 (2021)
• Dedicated setup to isolate plasma catalysis mechanisms
  C. Stewig, T. Urbanietz, L. Chauvet, M. Böke, A. von Keudell
  J. Phys. D: Appl. Phys. 54, 134005 (2021)
• Determining Chemical Reaction Systems in Plasma Catalytic Conversion of Hydrocarbons using Genetic Algorithms
  D. Reiser, A. von Keudell, T. Urbanietz
  Plasma Chem Plasma Process 41, 793 (2021)
• Excitation and dissociation of CO₂ heavily diluted in noble gas atmospheric pressure plasmas
  C. Stewig, S. Schüttler, T. Urbanietz, M. Böke, A. von Keudell
  J. Phys. D 53 125205 (2020)
• Non-equilibrium excitation of CO₂ in an atmospheric pressure helium plasma jet
  T. Urbanietz, M. Böke, V. Schulz-von der Gathen, A. von Keudell
  J. Phys. D 51, 345202 (2018)

Thesis

• Christoph Stewig, PhD thesis - 12/2022
  Excitation transfer between molecules in transient atmospheric pressure plasmas and its impact on plasma chemistry
• Steffen Schüttler, Bachelor thesis - 09/2018
  Plasma Catalysis of CO2 Reduction
• Thilo Romba, Bachelor thesis - 09/2018
  Plasma Conversion of CH4 O2 Mixtures
• Theresa Urbanietz, PhD thesis - ongoing
  Plasma Catalysis during Conversion of Methane/Oxygen/Hydrogen Gas Mixtures
• Boris Daniil, Bachelor thesis - 01/2021
  Simulation der Nachweisempfindlichkeit eines Atmosphärendruck-Massenspektrometers
• Steijn Vervloedt, PhD thesis - ongoing
  
• Daniel Henze, Bachelor thesis - 09/2022
  Measurement of carbon monoxide production in atmospheric pressure plasmas
• Siqi Yu, PhD thesis - ongoing
  
• Fatma-Nur Seferoglu, PhD thesis - ongoing
  

Further reading

• Unexpected O and O₃ production in the effluent of He/O₂ microplasma jets emanating into ambient air,
  D. Ellerweg, A. von Keudell, and J. Benedikt,
  Plasma Sources Sci. Technol. 21, 034019 (2012)