2717a.     PODGURSKI, H. H., AND EMMETT, P. H.  Adsorption Studies on Iron.  Am. Chem. Soc., 121st Meeting abs., March-April, 1952, p. 29-N.

        Adsorption characteristics of various Fe catalysts and Fe samples for H₂ and CO have been evaluated from 10^-2 to 700 mm. Hg pressure between –195° and –200°.  No evidence could be found on bulk Fe catalysts for the “solubility” effect noted by Beeck and coworkers for H₂ in thin metal films of Fe and Ni between –195° and 0°.  On no surface studied was the activated adsorption of H₂ at –195° sufficient in quantity to cover the free Fe surface with a layer of H atoms; however, for a singly promoted Fe catalyst (2-10% Al₂O₃), the rapid adsorption of H₂ at –195° was equivalent to adsorption as atoms on about 2/3 of the “free Fe surface”.  Type B activated adsorption of H₂ on promoted Fe catalysts at and >100° is very pressure-sensitive, and at a pressure of 10^-2 mm. Hg apparently becomes very small relative to Type A adsorption (chemisorbed at –78°).  The chemisorption of CO at –195° to –78°, which seems to be satisfactory for measuring the free Fe surface of catalysts and thin evaporated Fe films, covers only about 10% of the surface of very pure Fe wire, Fe powder from the reduction of pure Fe₂O₃, and Fe powder from Fe carbonyl.  The ratio of Type B H₂ adsorption to Type A appeared to increase as the ratio of promoter to Fe content was increased in synthetic NH₃ catalysts.