Catalytic effects on methanol oxidation produced by cathodization of platinum electrodes

Platinum surface modification with cerium species and the effect against the methanol anodic reaction

“…The same cathodic potential perturbation applied to the electrode immersed in supporting electrolyte free of cerium species produces the inhibition of hydrogen ad-atom formation by 65% of the platinum surface, in agreement with results shown in [27]. It was already discussed in literature [27] the unusual patterns developed in Pt voltammetric profiles after the cathodic incursion within the net hydrogen evolution region. Thus, the contribution of partial inhibition of hydrogen adsorption due to cathodization in a cerium-free supporting electrolyte has to be subtracted from the global inhibition in order to isolate only the cerium effect.…”

“…(1). When the potential is cycled afterwards until 1.75 V, two welldefined peaks are observed at 0.94 and 1.20 V, being the latter due to single PtO anodic formation from a hydrogenated platinum surface [27,29,30]. Besides, a current contribution all along the double layer is evidenced, attributed to surface cerium-containing species (Fig.…”

“…In the case of applying a cathodic potential perturbation in acid solution a decrease in the number of active hydrogen ad-species occurs [27]. Thus, the term DQ o H indicates the real available hydrogen ad-atoms that can be substituted by cerium species, and is defined as DQ o H ¼ Q Ht À Q Hcpp , being Q Ht the total hydrogen ad-atom charge density and Q Hcpp the charge after applying the same cathodic potential perturbation as applied to electrodeposite the cerium species but in the supporting electrolyte.…”

Carbon supported Pt, Ru and Mo catalysts for methanol electrooxidation

“…In a previous work [17], we have found that surface electrochemical pretreatments usually lead to surface and structure modifications producing large electrocatalytic improvements of current and power efficiencies when using methanol as fuel [17]. The surface pretreatment involves a net cathodic polarization in the hydrogen evolution potential region.…”

“…Results and discussion 3.1. a cleanness of the electrode and an ulterior restructuration [17]. The effect is important on binary and ternary platinum alloys because it seems to produce a complete reduction of salts precursors.…”