| 摘要 |
The present invention is a coated hydrogenation catalyst that includes a porous support material, an active metal component and a silica precursor, wherein the support material is impregnated with the active metal component and then contacted with the silica precursor. After impregnation, the support material is calcined to form a SiO2 layer. The active metal component can be one or more Group VIII metals, metal oxides, metal sulfides or metal carbides. The support material for the coated catalyst is kieselguhr, alumina, silica or silica-alumina. In a preferred embodiment, the active metal component is platinum, palladium, rhodium, rhenium or iridium and the catalyst includes a zeolite component. The coated catalyst is prepared by first impregnating the support material with the active metal component and then contacting the silica precursor to form an impregnated catalyst. The impregnated catalyst is then calcined to form the coated catalyst having a SiO2 layer. The impregnation with the active metal component and the incorporation of the silica precursor can be repeated two or more times to form a plurality of SiO2 layers on the coated catalyst. |
