Amorphous PdZr alloys for water electrolysis cathode materials

Amorphous Pd_0.35Zr_0.65 alloys prepared by a melt—quench technique were investigated for their possible use as water electrolysis cathodes. The Tafel—Volmer reaction route of the hydrogen electrode reaction was concluded. Kinetic parameter values of the constituent steps were evaluated by a transient technique. The electrocatalytic activity for cathodic hydrogen evolution on the as-obtained electrode was 10² times lower than Pd foil electrodes, but it was improved after the electrodes were treated in acids, typically aqueous HF. The activity in the highest state exceeds that of Pd by one order of magnitude. SEM and XPS observations indicated that the improvement in activity is due to increased surface Pd concentration after removal of a Zr-enriched surface layer which was produced during fabrication of the amorphous alloy specimens. Crystalline alloy electrodes prepared by heat treatment of the amorphous alloy were very brittle but showed electrocatalytic activity close to that of the amorphous electrodes.