Spectroscopic and morphological studies on the electrooxidation of Pt–Ni alloys in HCl solution

Investigation on the potential-dependent anodic oxidation of a Pt11Ni89 alloy electrode has been performed in an HCl solution. Spectroscopic information of UV–vis absorption and in situ Raman scattering shows that the alloy undergoes selective Ni dissolution and simultaneous Pt dissolution successively with the increase of the applied potential. The measurements of SEM–EDX, AFM and XRD at selected potentials reveal that Pt enrichment occurs in the alloy degradation accompanying diversiform morphological evolution such as cracks from stress corrosion, ultrafine pores by selective dissolution, and flaky nanoporous films involving simultaneous dissolution and potential-accelerated replacement reaction between Ni in the alloy and the dissolved PtCl62-. Moreover, the nanoporous films display high electrocatalytic activity toward the methanol oxidation.