Progress towards preparation of high-surface-area rare-earth oxides

Abstract

A series of high-surface-area rare-earth oxides has been prepared by precipitation from aqueous solution as either the hydroxide or the carbonate, followed by controlled dehydration, acetone washing, vacuum drying and calcination at ca. 600 °C. The materials have been characterised by X-ray diffraction (XRD), transmission electron microscopy (TEM), infrared spectroscopy (IR) and surface analysis. Precipitation by hydroxide produces a higher surface area for the lighter rare earths, whereas precipitation by carbonate is superior for the heavier members. By judicious choice of method, pure oxides (containing only trace amounts of surface carbonate) with surface areas > 50 m² g^–1 can be obtained for all rare earths studied. No microporosity was observed in any of the oxides.