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Nonthermal plasma (NTP) can oxidize and decompose particulate matter (PM) of diesel engines at low temperatures (≤200°C), exhibiting good application prospects. PM samples were collected under different diesel engine loads and were oxidized using an NTP method. The volatile fraction (VF) mass fraction of the PM samples decreases under low engine loads (<70%) and increases under high engine loads (≥70%) after the NTP treatment. NTP can remove aldehyde groups in PM and weaken the volatilization of PM. A higher temperature is needed for the VF to reach its maximum volatilization rate after the NTP treatment. The relative content of the small molecules is significantly higher after the NTP treatment. [ABSTRACT FROM AUTHOR]

To reveal the effect of reaction temperature on the reduction of diesel particulate matter (PM) by non-thermal plasma (NTP) using oxygen as a gas source. The changes in the microcrystalline structure and the elemental state of PM before and after NTP oxidation at different temperatures were explored by Raman and X-ray photoelectron spectroscopy. After NTP oxidation, the disorder in the PM microcrystal structure and the amorphous carbon structure was reduced. The full width at half maximum (FWHM) of the D1 and D3 peaks decreased, and the FWHM of the G peak increased slightly. During the oxidation of PM, the carbon microcrystals grew and became restructured, and the graphitization of PM increased. After NTP oxidation, the content of O in PM increased as the reaction temperature increased, resulting in a gradual change in the binding form of O with C from C-O to C=O. The ability of temperature rise to promote the oxidation activity of NTP was gradually weakened for the thermal decomposition of NTP active substances. The microcrystalline structure and the occurrence state of C and O of PM changed with reaction temperature, indicating that the oxidizability of NTP on PM differed at different reaction temperatures. [ABSTRACT FROM AUTHOR]