CO₂dissociation using the Versatile atmospheric dielectric barrier discharge experiment (VADER)

Abstract

Dissociation of CO 2 is investigated in an atmospheric pressure dielectric barrier discharge (DBD) with a simple, zero dimensional (0-D) chemical model and through experiment. The model predicts that the primary CO 2 dissociation pathway within a DBD is electron impact dissociation and electron-vibrational excitation. The relaxation kinetics following dissociation are dominated by atomic oxygen chemistry. The experiments included investigating the energy efficiencies and dissociation rates of CO 2 within a planar DBD, while the gas flow rate, voltage, gas composition, driving frequency, catalyst, and pulse modes were varied. Some of the VADER results include a maximum CO 2 dissociation energy efficiency of 2.5 ± 0.5%, a maximum CO 6 2 dissociation rate of 4 ± 0.4 ×10 − mol CO 2 /s (5 ± 0.5% percent dissociation), discovering that a resonant driving frequency of ∼30 kHz, dependent on both applied voltage and breakdown voltage, is best for efficient CO 2 dissociation and that TiO 2 , a photocatalyst, improved dissociation efficiencies by an average of 18% at driving frequencies above 5 kHz.

Effect of Argon or Helium on the CO2 Conversion in a Dielectric Barrier Discharge

“…We believe that this is one of the reasons for the higher CO 2 conversion upon addition of Ar or He. A similar explanation was also recently given by Lindon et al…”

“…A large number of experiments have been performed already in pure CO 2 , but also mixed with CH 4 , H 2 , or H 2 O, to form value‐added chemicals. Moreover, a few papers have reported on the mixing of CO 2 (and CH 4 ) with a rare gas, such as He or Ar . Pinhao et al investigated CO 2 /CH 4 /He mixtures in a DBD and observed that the addition of He results in a drop in the breakdown voltage and it enhances the conversion of both CO 2 and CH 4 .…”

“…Also Gouilard et al reported that He dilution yields higher conversions of CO 2 and CH 4 in a DBD, which they attributed to Penning ionization. Lindon et al compared a DBD operating in pure CO 2 and in a 60/40 CO 2 /Ar mixture, and found that the CO 2 conversion and energy efficiency were greatly improved upon addition of Ar, and they suggested that this was due to a reduction in the plasma breakdown voltage and an increase in the CO 2 + population, due to charge exchange with argon ions. Finally, Ozkan et al investigated the conversion of CO 2 and CH 4 in a DBD with multi‐electrodes and observed an increase in conversion of both CO 2 and CH 4 upon addition of Ar or He.…”

Understanding CO2 decomposition in microwave plasma by means of optical diagnostics

“…These anthropogenic activities at the same time are the main sources of CO 2 emission, which is believed to be in a strong relation to the greenhouse effect and so‐called global warming. Among the different approaches proposed nowadays for reducing the CO 2 pollution, the plasma‐based conversion of CO 2 into the valuable chemicals represents an extremely useful option . Under certain conditions, low‐temperature plasma can be an ideal environment for CO 2 conversion, which happens due to the formation of charged highly energetic species that can activate chemical reactions difficult or impossible to realize using ordinary thermal mechanisms .…”

Synthesis of Micro- and Nanomaterials in CO2and CO Dielectric Barrier Discharges

“…In this paper, we study the formation of carbonaceous solid products in pure CO 2 and CO Dielectric Barrier Discharge (DBD) systems, which represent a popular NTP approach for carbon dioxide decomposition . Interestingly, coke deposition is mostly not observed in such DBD reactors when working with CO 2 .…”