Trimesic acid assisted synthesis of cerium-manganese oxide for catalytic diesel soot elimination: Enhancement of thermal aging resistibility

Abstract In this work, trimesic acid was introduced in the preparation of cerium-manganese oxide, and its effect on thermal aging resistibility for catalytic diesel soot elimination was investigated systematically. The prepared catalysts were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), N2 adsorption–desorption, X-ray diffraction (XRD), Raman spectra, X-ray photoelectron spectroscopy (XPS) and H2-temperature programmed reduction (H2-TPR). The experimental results show that trimesic acid addition has no significant effect on the morphologies of cerium-manganese oxide catalyst, and also contribute litter to the suppression of catalyst particles sintering and textual features destroying. In addition, the crystal structure and high-temperature (800 °C) phase separation of CeO2-MnOx solid solution are not improved by the trimesic acid modification. But, noteworthily, trimesic acid assisted synthesis can obviously promote Mn4+ generation and keep up oxygen vacancy concentration and hence improve the product of highly active oxygen species (especially O 2 - ) of CeO2-MnOx catalyst during the thermal aging process. Furthermore, trimesic acid assistance can significantly alleviate the loss of CeO2-MnOx metal-support interaction caused by thermal aging, and maintain the ability to supply active oxygen at low-temperature (approximately 200–400 °C). Finally, after thermal aging at 800 °C for 12 h, the trimesic acid assisted synthesized CeO2-MnOx catalyst shows significantly better catalytic soot oxidation activity. Thus this work reveals that besides stabilizing textual and structural properties, stabilizing and optimizing electronic structure is another feasible pathway to enhance the thermal aging resistibility of CeO2-based soot oxidation catalysts.