Successive potential cycling of a Pt plate electrode was conducted in H 2 O 2 -containing 0.5 mol dm À3 H 2 SO 4 in the presence of metal ions such as Fe (Fe 2þ , Fe 3þ ), Ce (Ce 3þ , Ce 4þ ), and Mn (Mn 2þ ) ions. First, the potential cycling in 294 mmol dm À3 H 2 O 2 þ 0.5 mol dm À3 H 2 SO 4 without any metal ions confirmed the weight loss of the Pt electrode, which implies Pt dissolution. When the metal ions were added to the solution, the Pt electrode dissolution during the potential cycling was very significant; the Pt weight sharply decreased in the presence of both Fe 2þ and H 2 O 2 . In addition, this enhanced Pt dissolution depended on both the Fe 2þ and H 2 O 2 concentrations, and the maximum Pt weight loss (257 lg) was obtained at the Fe 2þ and H 2 O 2 concentrations of 10 and 294 mmol dm À3 , respectively. The Fe 2þ and H 2 O 2 concentration dependences of the Pt dissolution also correlated with the consumption rate of H 2 O 2 . These results revealed that the Fe 2þ and H 2 O 2 synergically enhanced the Pt dissolution rate. V C 2014 AIP Publishing LLC.

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