Non-thermal plasma-assisted catalytic NO_x storage over Pt/Ba/Al₂O₃ at low temperatures

NO_x storage performances have been investigated on a Pt/Ba/Al₂O₃ catalyst by comparison using two types of non-thermal plasma (NTP) reactor: the "PDC system" reactor and the "PFC system" reactor. In the PDC system, the catalyst was placed in the discharge space and was activated by the plasma directly, whereas in the PFC system, the plasma reactor was followed by the catalyst. The results showed that the NO_x storage capacity (NSC) of the Pt/Ba/Al₂O₃ catalyst was significantly enhanced by the non-thermal plasma in the PDC and PFC system, and the PDC system exhibited better promotional effect than the PFC system in the temperature range of 100-300 °C. The NSC of the catalyst was increased with the increase of the input energy density both in the PDC and PFC system due to the higher NO oxidation at higher input energy density. It was also found that the ionic wind induced by plasma in the PDC system enhanced the quantity of the NO adsorbed onto the catalyst surface and therefore could react with the O-radical to form more NO₂, and thus promote the formation of nitrate on the catalyst.