Berlin 2001 – scientific programme

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P: Plasmaphysik

P 12: Plasma Wall Interaction, Diagnostic and Low Temperature Discharges (Poster Session)

P 12.12: Poster

Friday, April 6, 2001, 12:30–15:00, AT2

Infrared Absorption Spectroscopic Studies of the CO₂ Conversion in a Low Pressure Glow Discharge — •Frank Hempel¹, Jürgen Röpcke¹, Frank Miethke², and Hans-Erich Wagner² — ¹Institute of Low Temperature Plasma Physics (INP), Friedrich-Ludwig-Jahn-Str. 19, 17489 Greifswald, Germany — ²Institute of Physics, Ernst-Moritz-Arndt University Greifswald, Domstr. 10 a, 17489 Greifswald, Germany

The time and spatial dependence of the chemical conversion of CO₂ to CO were studied in a closed glow discharge reactor (p = 50 Pa, I = 2..30 mA) consisting of a small plasma zone and an extended stationary afterglow. Tunable infrared diode laser absorption spectroscopy has been applied to determine the absolute ground state concentrations of CO and CO₂. After a certain discharge time an equilibrium of the concentrations of both species could be observed. The spatial dependence of the equilibrium CO concentration in the afterglow was found to be varying less than 10 %. The feed gas was converted to CO more predominantly between 45 % and 60 % with increasing discharge current. The formation time of the stable gas composition decreased with the current too. For currents higher than 10 mA the conversion rate of CO₂ to CO was estimated to 1 x 10¹³ molecules J⁻¹. Based on the experimental results a plasma chemical modeling has been established.