3339.     SADEK, H., AND TAYLOR, H. S.  Heterogeneity of Catalyst Surfaces for Chemisorption.  III.  Metallic Nickel.  Jour. Am. Chem. Soc., vol. 72, 1950, pp. 1168-1175; Chem. Abs., vol. 44, 1950, p. 5199.

        Heterogeneity of the surfaces of 6 different Ni catalyst preparations was confirmed with the technique devised by Taylor and Liang (abs. 3338) and H₂ as the adsorbate.  The adsorption at -195° were analyzed to determine the relative amounts of van der Waals adsorption and chemisorption of H₂ to show that different preparations adsorb different relative amounts of the 2 types.  The velocity of the H-D exchange reaction on Ni-Cr₂O₂ and Ni-ThO₂ was studied to support these findings.  There are marked differences in rates with activation energies of 0.45 and 2 kcal., respectively.  The data do not support an interpretation based either on solubility of H₂ in the lattice or an exothermic entry of H₂ into the Ni lattice at temperatures -195° to -78°.