| 摘要 |
PURPOSE:To enhance the durability of a catalyst, by forming a coating layer containing 1-10wt% of trivalent chromium oxide to the surface of silica cloth with a specific surface area of 5m<2>/g or less and silica purity of 96% or more, and further forming a second coating layer of alumina or silica. CONSTITUTION:Silica cloth (a specific surface area of 50-200m<2>/g, a pore size of 10-1,000Angstrom ) comprising silica with a specific surface area according to a N2-adsorbing BET measuring method of 5m<2>/g or less and silica pruity of 96% or more is immersed in an aqueous chromium nitrate solution and the impregnated cloth is dried by air and further dried at 100-200 deg.C. Subsequently, this cloth is subjected to thermal decomposition at 500-900 deg.C to form chromium oxide. In the next step, the treated cloth is immersed in a boehmite alumina solution and, after air drying, baked at 400-800 deg.C to form a cloth carrier. This cloth carrier is immersed in an aqueous platinum chloride solution or an aqueous vanadium chloride solution and, after drying, decomposed and baked at 500- 750 deg.C. |
