Impact of thermal oxidation on morphological characteristics of cordierite and attapulgite substrate materials

The diesel particulate filter (DPF) is one of the most effective devices for reducing particulate emission, where the continuous DPF regeneration is necessary for maintaining filter efficiency. There is currently a lack of investigation on the effect of thermal oxidation on morphological characteristics of substrate materials. In this study, the cordierite (Cord) and attapulgite (ATP) powders were mixed with CeO₂, serving as substrate and catalyst, respectively. The soot particles were collected from a heavy-duty diesel engine. Through the thermal oxidation from 450°C to 650°C, it was found that the special fibrous or rod-like structure of ATP produced more pore volume and surface area, as well as an efficient heat recovery mechanism after thermal oxidation. The block-like structure of Cord only acted as a substrate, maintaining its intact crystalline structure during thermal oxidation. Notably, the oxidation reactivity of ATP/CeO₂/Soot was higher than Cord/CeO₂/Soot because the ATP generated more catalyst active sites and sufficient contact area for the soot-oxygen-CeO₂ reaction. This study expands the potential application of ATP as DPF substrate material.