Keywords: Soot oxidation; ceria-zirconia; praseodymia modified ceria-zirconia; tight contact

Abstract

In this investigation, modified and pure ceria-zirconia catalysts were prepared by a surfactant-assisted hydrothermal method. Analytical techniques such as Powder X-ray diffraction (XRD), BET-BJH-surface area, Thermogravimetry/differential thermogravimetry (TG/DTG), Raman spectroscopy (RS), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM) and Temperature Programmed Reduction (TPR) were utilized to characterize the structures of the prepared catalysts. The formation of a cubic fluorite structure of ceria-zirconia was inferred from XRD analysis. The oxidation states of the metals present were studied using XPS. The objective of this work was to investigate the effect of cerium content and the influence of praseodymium in promoting the soot combustion activity of ceria-based catalysts. Our study showed that the order of activity depends on the amount of the cerium and modified metal. Modification of the ceria-zirconia catalysts with praseodymium enhanced the catalytic activity to a great extent. Notably, the reactivity of the soot combustion reaction was found to correlate with the improved redox properties and the synergistic effect of praseodymium and the ceria component.