Insight into the Synergetic Effects of NTP-La1–xAgxMnO₃ on Soot Oxidation at Low Temperatures

Nonthermal plasma (NTP)-assisted catalysis technology is proposed to enhance the rate of catalytic soot combustion at low temperatures. This study evaluated the performance of NTP technology combined with silver-doped La1–xAgxMnO3 on the catalytic soot combustion under simulated conditions of 10% oxygen and at 200 °C. Results showed that a combination of NTP and La0.5Ag0.5MnO3 had a super strong synergetic effect below 200 °C and thus led to a much higher rate of soot combustion than the simple additive effect of NTP and a bare catalyst. In the dry gas flow or low water vapor content, the best catalytic behavior for soot combustion was obtained at low reaction temperatures under loose contact between soot and the catalyst, i.e., more than 90% soot conversion and CO2 selectivity were simultaneously achieved using NTP-La0.5Ag0.5MnO3 hybrid for soot oxidation at 200 °C. Even at 10 vol % water vapor content, soot conversion was still 83%, and the CO2 selectivity was more than 90%, indicating that La0.5Ag0.5MnO3 possesses good water resistance. Based on a series of comparative studies, the synergetic mechanism of NTP-La1–xAgxMnO3 synergetic catalysis at low temperatures was proposed.