Volumetric and calorimetric study of the adsorption of hydrogen, at 296 K, on supported nickel and nickel–copper catalysts containing preadsorbed carbon monoxide

Abstract

The present volumetric data comfirm that, upon adsorption of carbon monoxide at 296 K on nickel surface atoms, both linear and bridged adspecies are formed in a proportion which depends upon the amount of copper in the nickel–alloy copper. There is no chemical interaction at 296 K between carbon monoxide and hydrogen in a mixed adsorbate layer. However, the present calorimetric data indicate that preadsorbed carbon monoxide induces a surface energetic heterogeneity with respect to the adsorption of hydrogen at 296 K. It has been attempted to show that, for all the nickel and nickel—copper catalysts, induced heterogeneity may be related to the density of states at the Fermi level.