Hybrid TiO2 based plasma-catalytic reactors for the removal of hazardous gasses

• Hybrid plasma-catalytic reactor with TiO2 was investigated for oxidation of NOx/SOx.
• Plasma activated TiO2 enhances the oxidation of both NO and SO2.
• TiO2 effect was more pronounced for SO2 which was not removable by plasma alone.
• Plasma-produced oxygen species are one reason for activity of TiO2 surface.

The paper deals with the removal of hazardous gasses by hybrid plasma-catalytic reactors. Coaxial dielectric barrier discharge (DBD) reactor was used for the generation of plasma and a layer of catalytic TiO2 powder was pressed on the inner wall of the plasma reactor to allow direct contact between the plasma and catalyst. The reactor was used for the oxidation of NO or SO2 in the mixture with 10% O2 and N2 balance. In some cases, H2O vapor or CO2 was added to the mixture to investigate the effect of these exhaust gas constituents on the NO removal. The presence of TiO2 coating in the reactor zone increased the oxidation efficiency for both treated gasses but was more pronounced in the case of SO2. There were also some differences regarding the effect of temperature and humidity. It was necessary to use higher temperatures to increase the removal efficiency of NO by TiO2 catalyst compared to SO2. In humid conditions, the removal of NO was further increased by the TiO2 catalyst while the enhancement of SO2 removal by catalyst was not detectable.