Enhanced Degradation of Gaseous Xylene Using Surface Acidized TiO₂ Catalyst with Non-thermal Plasmas

A plasma driven catalyst reactor was applied to the degradation of gaseous xylene combined with the TiO₂ catalyst processed by an acidized treatment, which promoted both Lewis and Bronsted acid sites on the surface of the catalyst. Results showed that the acidized TiO₂ performed much better than untreated TiO₂ in the degradation process. 92.48 % of 110 ppm xylene in air was decomposed by the acidized catalyst at 14 kV when the carrier gas was humid, meanwhile nearly all the destructed xylene was transformed to CO_x, with CO₂ selectivity reaching 85.62 %. However, under the dry condition, besides the conversion ratio and selectivity of CO_x achieved by various catalysts all decreased, it was also found that the acidized TiO₂ exhibited smaller advantage than untreated TiO₂ in the degradation process. It may be concluded that water vapor was not only beneficial to the destruction of xylene but also positively related with the surface catalytic activation of acidized catalyst. Finally, catalytic mechanisms with the acidized catalyst were briefly discussed.