ABSTRACT
Since catalyzed reactions take place on the surface of the catalyticalfy active material, the most efficient catalysts are those in which a high percentage of the active species is exposed to the reaction medium. The major objective in the preparation of supported catalysts is to have a high surface area of reduced metal deposited on a highly porous material. Supported metal catalysts are generally prepared by reducing a precurser metal salt which has been incorporated into or onto the support material. This supported salt is then dried and, possibly, calcined (heating in air) to modify its chemical composition. The final step is a reduction to give the supported metal. Even if the formation of a mixed metal compound is not favorable, some of the support material is usually trapped in the active metal precipitate.
