The effect on the electrocatalytic activity of the chemical interaction of selenium with palladium centers: oxygen reduction and methanol oxidation reactions in alkaline medium.

The chemical reactivity of two different selenium precursors (SeOand Se) with nanoparticulated palladium was studied in a simple aqueous phase synthesis to generate palladium selenides (PdSe). As confirmed by XRD, XPS, TEM and energy dispersive spectroscopy analyses, the products generated showed different degrees of selenization according to the nature of the chemical precursor. Such degree of selenization was more important with elemental selenium, in contrast to SeO. Surface electrochemistry and CO stripping in alkaline medium, clearly revealed the different interactions and stability of PdSeachieved with the Pd/C precursor depending on the selenium source. The electrocatalysis of the oxygen reduction reaction was also influenced by the Se source, first in the different degree of reactivity, and second in the selectivity of the reduction product between HO and HO, as well as the tolerance to the methanol oxidation reaction.