Effect of Pt/γ-Al₂O₃ catalyst on nonthermal plasma decomposition of benzene and byproducts

This article presents the effects of different packing materials in dielectric barrier discharge (DBD) reactor on benzene removal efficiency to clarify the mechanism of combining efficiency between nonthermal plasma and catalyst over organic contaminants degradation. The influence of γ-Al ₂O₃ and Pt/γ-Al₂O₃ catalysts on benzene decomposition was examined by passing gaseous benzene through two DBD reactors, each packed with one of the catalysts mentioned above. Concentrations of benzene, CO, CO₂, NO₂, and NO were measured and decomposition efficiency (of benzene), selectivity (of CO and CO₂), and carbon balance were calculated to compare the effects of γ-Al ₂O₃ catalyst with that of Pt/γ-Al₂O ₃ catalyst in DBD reactors on benzene degradation. Data showed that at the same input energy density, benzene decomposition efficiency increased by about 20%, whereas the amount of CO released decreased by about 50% when using Pt/γ-Al₂O₃ catalyst. From the Arrhenius plot, the activation energy of Pt/γ-Al₂O₃ catalyst was calculated to be 3.01 kJ/mol, which turned out to be less than that of γ-Al₂O₃ catalyst by 57%. Further, the amounts of NO₂ and NO released from the reactor when using Pt/γ-Al ₂O₃ catalyst were only about 1/3 and 1/6 of that when using γ-Al₂O₃ catalyst, respectively. Therefore, Pt/γ-Al₂O₃ is a better catalyst because of the higher benzene decomposition efficiency, lower activation energy, and less byproducts generated when it was used in DBD reactor.