| 摘要 |
The invention relates to a process for producing supported shell catalysts comprising noble metals by UV photoreduction of noble metal salt precursors fixed to a support. For this purpose, the shaped supported body is impregnated with suitable noble metal salts which are then reduced to the metals in a zone close to the surface by means of UV radiation, preferably in the absence of a chemical reducing agent. The metal salts in the interior of the pellets which have not been irradiated and therefore have not been reduced are extracted using a solvent.The noble metal shell catalysts produced in this way can be used for many heterogeneously catalyzed reactions such as hydrogenations and oxidations.According to the invention, Pd/Au shell catalysts on porous ceramic supports, e.g. SiO2 shaped bodies, produced by this process can be used in the synthesis of vinyl acetate.
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