Volumetric and calorimetric study of the adsorption of hydrogen, at 296 K, on silica-supported nickel and nickel–copper catalysts

Abstract

A volumetric and microcalorimetric study of the adsorption of hydrogen, at 296 K, on a series of silica-supported nickel and nickel–copper catalysts was carried out. Alloying with copper decreases both the affinity of nickel for hydrogen and the heat of adsorption of hydrogen. The hydrogen coverage, under standard conditions, on a given alloy is correlated to the saturation magnetization of the metal atoms in the alloy. The decrease of the differential heats of adsorption of hydrogen, resulting either from alloying or from the heterogeneity induced by pre-adsorbed hydrogen, can be correlated with the changes of electron density of states, at the Fermi level, for the surface nickel atoms.