Taming microwave plasma to beat thermodynamics in CO2 dissociation

TitleTaming microwave plasma to beat thermodynamics in CO2 dissociation
Publication TypeJournal Article
Year of Publication2015
AuthorsG. van Rooij, D. van den Bekerom, N. den Harder, T. Minea, G. Berden, W. Bongers, R. Engeln, M. Graswinckel, E. Zoethout, M.CM van de Sanden
JournalFaraday Discussions
Volume178
IssueDec
Pagination233-248
Abstract

The strong non-equilibrium conditions provided by the plasma phase offer the opportunity to beat traditional thermal process energy efficiencies via preferential excitation of molecular vibrations. Simple molecular physics considerations are presented to explain potential dissociation pathways in a plasma and their effect on energy efficiency. A common microwave reactor approach is evaluated experimentally with Rayleigh scattering and Fourier transform infrared spectroscopy to assess gas temperatures (exceeding 104 K) and conversion degrees (up to 30%){,} respectively. The results are interpreted on basis of estimates of the plasma dynamics obtained with electron energy distribution functions calculated with a Boltzmann solver. It indicates that the intrinsic electron energies are higher than is favorable for preferential vibrational excitation due to dissociative excitation{,} which causes thermodynamic equilibrium chemistry to dominate. The highest observed energy efficiencies of 45% do indicate that still non-equilibrium dynamics had been at play. A novel approach involving additives of low ionization potential to tailor the electron energies to the vibrational excitation regime is proposed.

DOI10.1039/C5FD00045A
Division

MaSF

Department

MaSF-E

PID

3a7523c9a5213dcb97e3fcaa043cc269

Alternate TitleFaraday Discuss.
LabelOA
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