Akira Nakazawa

Effects of metal ions on Pt electrode dissolution in H2SO4 solution enhanced by the presence of H2O2

Successive potential cycling of a Pt plate electrode was conducted in H2O2-containing 0.5 mol dm−3 H2SO4 in the presence of metal ions such as Fe (Fe2+, Fe3+), Ce (Ce3+, Ce4+), and Mn (Mn2+) ions. First, the potential cycling in 294 mmol dm−3 H2O2 + 0.5 mol dm−3 H2SO4 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 Fe2+ and H2O2. In addition, this enhanced Pt dissolution depended on both the Fe2+ and H2O2 concentrations, and the maximum Pt weight loss (257 μg) was obtained at the Fe2+ and H2O2 concentrations of 10 and 294 mmol dm−3, respectively. The Fe2+ and H2O2 concentration dependences of the Pt dissolution also correlated with the consumption rate of H2O2. These results revealed that the Fe2+ and H2O2 synergically enhanced the Pt dissolution rate.