Storage and reduction of NO by combining Sr-based perovskite catalyst with nonthermal plasma.

A novel NO storage and reduction (NSR) system is developed for NO removal by integrating Sr-based perovskite catalyst with nonthermal plasma (NTP)-assisted process. In this hybrid system, Sr-based perovskite catalyst is applied for NO adsorption in the lean-burn condition while NTP is used as a desorption-reduction step to convert NO into N under rich-burn condition. Innovative Sr-based perovskites including SrKMnCoO/BaO/AlO (SKMCBA), SrKMnCeO/BaO/AlO (SKMCeBA), and SrKCoNiO/BaO/AlO (SKCNBA) are successfully prepared by impregnation method. Results indicate that SKMCBA possesses the highest NO trapped (214 μmole NO/g) at 400 °C among 3 Sr-based perovskites investigated. High performance of SKMCBA for NO adsorption is mainly attributed to the addition of Mn and Co which own good oxidation ability. Further, SKMCBA is combined with NTP-assisted process for NO reduction. Result indicates that NO conversion achieved with NTP-assisted process reaches 83% with the applied voltage of 18 kV and frequency of 10 kHz in the absence of reducing agent. Additionally, various reducing agents including hydrogen (H), carbon monoxide (CO), and propene (CH) are introduced, individually, into the NTP reduction process, and the results indicate that performance of NSR with NTP can be effectively enhanced. Especially, 100% NO conversion is achieved with H-NTP. This study demonstrates that reduction of NO via NTP-assisted process is promising.