TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preparation (Claimed): Preparation of (I) (comprising (A) and (B)) comprises forming a coating by heat treating (A) after applied with a coating composition, which is obtained by mixing the first metal oxide powder together with a fluid raw material composition containing a raw material of a second metal oxide of alumina, zirconia, titania, iron oxides, oxides of rare earth elements, alkali metal oxides and/or alkali earth metal oxides, at a shear rate of 1000 sec-1 or higher. Preferred Components: The diameters of nanopores of the nanoporous metal oxide material is 5 (preferably 2) nm or less. The average particle size of the first metal oxide powder is 0.01-50 microns. The content of the first metal oxide powder is 10-60 wt.% of the total amount of metal oxides constituting the coating. The first metal oxide powder is sealed in the matrix and is supported on the surface of (A). The raw material of the second metal oxide is colloidal particles of alumina, zirconia, titania, iron oxides, oxides of rare earth elements, alkali metal oxides and alkali earth metal oxides, and salts of aluminum, zirconium, titanium, iron, rare earth elements, alkali metals and/or alkali earth metals. Preferred Composition: (I) further comprises a noble metal supported on the surface of the first metal oxide powder; and a noble metal supported on the surface of the coating. The fluid raw material composition is a colloidal solution containing colloidal particles of alumina, zirconia, titania, iron oxides, oxides of rare earth elements, alkali metal oxides and/or alkali earth metal oxides. The fluid raw material composition is a metal salt solution containing salts of aluminum, zirconium, titanium, iron, rare earth elements, alkali metals and/or alkali earth metals. Preferred Process: The powder is mixed together with the fluid raw material composition at a shear rate of 10000 sec-1 or higher. The preparation of (I) further includes a step of supporting a noble metal on the surface of the first metal oxide powder or coating. EXAMPLE - Aluminum trioxide colloid (35 wt.%), zirconium solution (13.5 wt.%), zirconium oxide powder (16.5 wt.%) and cerium solution (35 wt.%) were mixed in the proportion, and then diluted with methanol to prepare a solution (or a dispersion) with a solid concentration of 12 wt.%. The solution was mixed for 2 minutes with the homogenizer at a shear rate of 20000 sec-1, and then gently mixed (stirring rate of 20 rpm) for about one minute to remove air bubbles from the resulting solution to obtain a coating composition. Subsequently, each of the substrates was immediately immersed in the obtained coating composition for 1-10 seconds and excessive coating composition was removed by gravity and shaking after the substrate was pulled out. After being placed horizontally, the substrate was gently dried at room temperature for 5-10 minutes, dried with warm air (60-100degreesC) at a wind velocity of 2-5 m/s for 5 to 10 minutes, precalcinated at 250degreesC for approximately 30 minutes in the air atmosphere, and further cooled for 5-10 minutes with normal temperature air at a wind velocity of 2-5 m/s. After repeating such treatments twice, the substrates were calcinated for approximately 60 minutes at 500degreesC in the air atmosphere, and the catalyst supports with metal oxide coating formed on the substrate surface were obtained.