Core-shell MnCeOx catalysts for NO oxidation and mild temperature diesel soot combustion

Environmental contamination such as soot particles and NOx has aroused extensive attraction recently. However, the main challenge lies in the oxidation of soot at mild temperature with the assistance of NOx. Here, a series of core-shell MnCeOx catalysts were successfully synthesized by hydrothermal method and employed for low-temperature catalytic oxidation of soot in the presence of NOx. X-ray diffraction (XRD), inductively coupled plasma-optical emission spectrometry (ICP-OES), energy-dispersive X-ray spectroscopy (EDS), transmission electron microscopy (TEM), N2 adsorption/desorption, H2-temperature programmed reduction (H2-TPR), O2-temperature programmed desorption (O2-TPD), X-ray photoelectron spectroscopy (XPS) and Raman analyses were conducted for identifying the structure of prepared catalysts and investigating redox properties of the core-shell mixed oxide, which shows excellent performance for NO oxidation and the T50 about 350 degrees C for soot oxidation. Besides, soot particle is oxided at 304 degrees C in the presence of NO, while T50 augments up to 340 degrees C in the absence of NO. In the NOxassisted elimination cases of soot, NO2 generated from NO in emission gas is generally reckoned as a facilitator which significantly reduces ignition temperature of soot particles. Possible catalytic mechanism over core-shell MnCeOx catalysts is also proposed in this paper.(c) 2022 Chinese Society of Rare Earths. Published by Elsevier B.V. All rights reserved.