Palladium and its alloys have been extensively studied because of their fac
ulty to store reversibly hydrogen isotopes. Here, the substitution of palla
dium with platinum is investigated. Thermodynamical studies have shown an a
nomalous behaviour regarding to the classical models. This original behavio
ur is explained by the study of the electronic structure of the binary soli
d solutions, The drastic decrease of the hydrogen solubility in the Pd-Pt a
lloys is accounted for by the filling up of the palladium conduction band b
y the valence electrons of platinum. The anomalous decrease of the stabilit
y of the hydride is explained by the large broadening of the valence band d
ue to the substitution. (C) 2001 Elsevier Science B.V. All rights reserved.