Temperature‐Programmed Oxidation of Soot in a Hybrid Catalysis‐Plasma System

Non‐thermal plasma (NTP) technology was applied to promote the temperature‐programmed oxidation (TPO) of soot over a perovskites type of La 0.8 K 0.2 MnO 3 catalyst. The O radicals originating from the decomposition of O 2 , as well as NO dissociation if nitrogen oxide were involved, reduce the ignition temperatures of soot. In NO‐O 2 ‐He, for example, the ignition temperature decreased to 240 °C from 290 °C as the voltage increased from 0 kV to 15 kV. The higher voltage also benefited the adsorption of NO molecules onto the catalyst surface (NO ad ). As a result, the maximum N 2 /NO ratio (conversion ratio of NO into N 2 ) rose from 23 % to 53 %. Some of the NO molecules were dissociated into N and O radicals in plasma, and hence, the N 2 /NO ratio was further enhanced due to the combination of N atoms. In any case, the redox process between NO x and soot proved to be important in soot oxidation.