Abstract: A plasma-assisted catalytic system for the selective catalytic reduction of NO with methane was investigated. NO₂, HCHO, CH₃NO, and CH₃NO₂ were the reactive intermediates generated by the plasma. The further reactions of these intermediates on the catalyst during the thermal catalytic stage resulted in the conversion of NO_x to N₂, which was verified by temperature-programmed surface reaction characterization. B₂O₃/γ-Al₂O₃ was the best catalyst with the maximum conversion of NO_x to N₂ increasing from 33.4% on γ-Al₂O₃ to 51.0% on 10 wt% B₂O₃/γ-Al₂O₃ at 300 ^oC. NH₃-TPD characterization showed that the acidity of the catalyst is important for the reduction of NO_x by the intermediates generated by the plasma. NO_x-TPD showed that the adsorbed NO_x species on the catalysts also played a role in the conversion of NO_x.

Key words: nitrogen oxide, selective catalytic reduction, boric oxide, alumina, cold plasma, temperature-programmed surface reduction