2007.     ---------------.  [KUMMER, J. T., AND EMMETT, P. H.]  Study of the Amount of Hydrogen Left on the Surface of a Reduced and Evacuated Iron Synthetic Ammonia Catalyst.  Jour. Phys. and Colloid Chem., vol. 55, 1951, pp. 337-345.

        To remove one of the uncertainties in measuring the adsorption of H₂ on metal catalysts, it is necessary to determine the amount of H on the catalyst at the start of the adsorption run.  To determine the amount of residual H present on samples of pure and of promoted iron synthetic ammonia catalysts use was made of H isotopes after the catalysts had been degassed for a number of hours at 500°.  The procedure is described.  It was found that promoted iron synthetic ammonia catalysts, but not pure iron catalysts, retain enough H after 24-hr. evacuation at high temperature (about 500°) to be equivalent to the covering of 5-35% of the metallic surface, or 1-10% of the part of the surface covered with promoter.  Accordingly, due account should be taken of this residual H in any adsorption measurements on promoted iron catalysts.