Effect of Temperature, Electrode Potential, and Bulk Composition on Hydrogen Electrosorption into Palladium-Ruthenium Alloys—Comparative Study with Other Binary Systems

The influence of temperature between 283 K and 328 K on hydrogen electrosorption into Pd-Ru alloys in the bulk composition range 87–100% at. Pd was studied voltammetrically and chronoamperometrically in 0.5 M H2SO4 solution. The maximum alloy ability to absorb hydrogen decreases with increasing temperature. The extent of hydrogen absorption/desorption hysteresis is slightly reduced with increasing temperature and markedly reduced with increasing Ru bulk content. Both increasing temperature and Ru bulk content results not only in a decrease in the thermodynamic stability of the hydride phase but also in an improvement in the kinetics of hydrogen electrosorption. Pd-Ru alloys containing more than ca. 97% at. Pd absorb more hydrogen than pure Pd, while further Ru additive results in a significant deterioration of the alloy ability to absorb hydrogen. The data on the influence of temperature and alloy bulk composition on the processes of hydrogen electrosorption in Pd binary alloys with Ru, Rh, Pt, and Au have been compared.