The interaction effect of catalyst and ash on diesel soot oxidation by thermogravimetric analysis

The interaction effect of catalyst and ash on commercial carbon black (Printex U, PU) oxidation is investigated using non-isothermal thermogravimetric analysis (TGA). The presence of commercial catalysts TiO 2 and CeO 2 decrease the start, peak and end temperatures of soot oxidation, and increase the comprehensive oxidation index. Compared with PU/TiO 2 mixture, PU/CeO 2 mixture has lower activation energy and higher comprehensive oxidation index because CeO 2 has the higher oxygen storage and better active oxygen generation capacities. The impact of CeO 2 is shown to be the most significant at 1:5 wt ratio between soot and catalyst among various ratios. Compared with pure PU, the comprehensive oxidation index for 1:5 wt ratio of PU/CeO 2 increases from 0.97*10 −7 % 2 min −2  °C −3 to 1.58*10 −7 % 2 min −2  °C −3 . The comprehensive oxidation index can further increase by adding ashes. Compared with PU/CeO 2 /Al 2 O 3 , PU/CeO 2 /MgO and PU/CeO 2 /CaSO 4 mixtures, PU/CeO 2 /ZnO mixture has the maximum comprehensive oxidation index. The most significant impact of potential ash on PU/CeO2 is observed with 1:5:5 wt ratio of PU/CeO 2 /ZnO among soot, catalyst and ash, which has the maximum comprehensive oxidation index 2.41*10 −7 % 2 min −2  °C −3 . The comprehensive oxidation index of 1:5:5 wt ratio of PU/CeO 2 /ZnO increases by 148% compared with pure PU. This work is beneficial to demonstrate the interaction mechanism of the catalyst and ash on soot oxidation process under O 2 /N 2 atmosphere.