Microscopic metals colloidal dispersions

Metal hydrogenation catalysts may be employed in any one of a variety of forms (a) macroscopic forms as wires, foils or granules (b) microscopic forms as powders obtained by chemical reduction, colloidal suspensions, blacks or evaporated metal films (c) supported catalysts where varying concentrations of metal are dispersed to a varying degree on a carrier such as alumina, silica or carbon. 

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