Dielectric Barrier Discharge Initiated Gas-Phase Decomposition of CO₂ to CO and C₆–C₉ Alkanes to C₁–C₃ Hydrocarbons on Glass, Molecular Sieve 10X and TiO₂/ZnO Surfaces

Abstract

Atmospheric Pressure Dielectric Barrier Discharge (APDBD) initiated decomposition of CO₂ and C₆–C₉ alkanes (in Ar carrier) with uncoated and TiO₂/ZnO coated glass surfaces, and under molecular sieve 10 X packing are presented in this study. Alkanes employed include 2-methylpentane, cyclohexane, n-hexane, n-heptane, n-octane, n-nonane and their decomposition products studied include C₁–C₃ hydrocarbons viz. CH₄, C₂H₄, C₂H₆ and C₃H₈. Generally the yields of all these C₁–C₃ products increased with discharge energy, however to a major extent the parent alkane structure controlled the relative concentration profiles of the individual products. Typically the slopes of the increase in various products yield varied from 0.025 to 0.25 ppm (v/v) mm V⁻¹. However, in the case of cyclohexane the total yield of methane, ethane and propane were only ∼20% of ethylene yield. Use of TiO₂ as well as TiO₂/ZnO coated central glass electrode in the APDBD apparatus showed ∼11% enhancement in $\hbox{CO}_{2} \rightarrow \hbox{CO}$ degradation efficiency. However, while overall 2-methylpentane decomposition reduced significantly to ∼30%, in case of n-octane its decomposition to the C₁–C₃ products remained unaffected. On the other hand under molecular sieve 10X packing, yield of CH₄ and C₂H₄ increased significantly in both cases.