Rare earth hydroxycarbonate materials with hierarchical structures: Preparation and characterization, and catalytic activity of derived oxides

A hydrothermal process is reported for the preparation of rare earth hydroxycarbonates LnOHCO(3) (Ln = Pr, Sm, Dy, Y) with hierarchical structures, such as dumbbell nanorod clusters, stacked lamellae and patched rods. All the hydroxycarbonate samples show fluorescence, and the emission wavelengths and intensity may be different for different samples. The hydroxycarbonate samples are generally stable under 380 degrees C, but will decompose to the respective oxides at higher temperatures. The oxides are tested for catalytic conversion of carbon monoxide to carbon dioxide. It reveals that all the rare earth oxides are active to the catalytic reaction, and Sm2O3 shows superior catalytic performance to the other oxides. (C) 2007 Elsevier Masson SAS. All rights reserved.