Pd-based bimetallic electrocatalysts for hydrogen oxidation reaction in acidic medium

A series of six bimetallic 10 wt% Pd-M (M: Ag, Co, Cu, Fe, Ru, Zn)/C and two monometallic 10 wt% Pd/C and 10 wt% Pt/C electrocatalysts were prepared via the wet impregnation method, physicochemically character-ized and electrochemically tested in the form of thin films towards their hydrogen oxidation reaction (HOR) activity in 0.1 M HClO4 at room temperature, using the rotating disk electrode (RDE) technique. 7.5 wt% Pd-2.5 wt% Ag/C was the most active among the Pd-based electrocatalysts, although less active than 10 wt % Pt/C, whereas 7.5 wt% Pd-2.5 wt% Cu/C and 7.5 wt% Pd-2.5 wt% Fe/C exhibited the lowest activity. The superiority of 7.5 wt% Pd-2.5 wt% Ag/C was mainly attributed to the electronic interaction between Ag and Pd on the electrocatalytic surface, which alters the chemisorptive properties of the active metal phase favorably for the HOR.