Structural effects on voltammograms of the high index planes of Pd in alkaline solution

Abstract

We have studied structural effects on voltammograms of the high-index planes of Pd (n(111)–(111), n(111)–(100), n(100)–(111) and n(100)–(110) series) in KOH solution. On the surfaces with (111) terrace, anodic peaks appear at 0.6, 0.75 and 1.07 V (vs RHE). The peaks at 0.6 and 1.07 V (vs RHE) are due to the oxides formed on the terrace, and the peak at 0.75 V (vs RHE) is assigned to oxide formation on the terrace edge and defects. On the surfaces with (100) terraces, anodic peaks are found at 0.75, 0.87 and around 0.5 V (vs RHE). The peaks at 0.75 and 0.87 V (vs RHE) are assigned to the oxide formation on the (100) terrace edge and (100) terrace, respectively. The peak around 0.5 V (vs RHE) originates from the release of absorbed hydrogen on the terrace. We have also studied cation effects on the voltammograms in LiOH, NaOH, KOH and CsOH. The voltammograms are independent of cation species.