MONOLAYER DISPERSION OF OXIDES AND SALTS ON SURFACE OF ZRO2 AND ITS APPLICATION IN PREPARATION OF ZRO2-SUPPORTED CATALYSTS WITH HIGH SURFACE-AREAS

The thermostability of ZrO2 can be improved by dispersing a layer of a n active component onto its surface in advance. The research results o f seven kinds of catalysts (ZrO2-supported MoO3, WO3, CuO, SO42-, NiO, FeSO4 and Fe2O3) show that the surface areas of the samples prepared by impregnating Zr(OH)(4) with the active components and then calcinin g at high temperature are much larger than those of the samples prepar ed with an ordinary method, namely, impregnating ZrO2 calcined at high temperature. The surface areas of the ZrO2-supported catalysts obtain ed in this way are several times that of pure ZrO2 calcined at the sam e temperature. The characteristic results show: (1) the active compone nts are dispersed on the surface of ZrO2 as monolayer; (2) there is a good corresponding relationship between the surface coverage and the s urface area of the sample; (3) as the loading of an active component c omes up to its utmost dispersion capacity, the surface area of the sam ple will be the largest. The mechanism responsible for these phenomena has been discussed.