Preparation and characterization of Ce-Mn-O composites with applications in catalytic wet oxidation processes

A series of Ce-Mn composites with different compositions was prepared by co-precipitation. All samples were characterized by x-ray diffraction (XRD), x-ray photoelectron spectroscopy (XPS), energy dispersive spectroscopy (EDS) and transmission electron microscopy (TEM). According to their size and chemical composition, two different kinds of particles were observed: (a) small crystallites of Ce-Mn solid solution (<7 nm), and (b) large particles of manganese oxides with different reduction degrees (>50 nm). These results were used to explain differences between the surface and bulk compositions of the samples as well as the specific surface area. Furthermore, from XPS studies, the presence of various Mn species with different oxidation states could be stated. This fact might clarify the exceptional catalytic behaviour of the samples for the catalytic wet oxidation of toxic organic compounds. Copyright (C) 2004 John Wiley Sons, Ltd.