Redox reaction of platinum in PbO-SiO2 melt

Redox reaction of platinum ion in 50 PbO.50 SiO2 (molar ratio) melt was ana lyzed electrochemically using cyclic voltammetry and chronopotentiometry, T he platinum ion in the melt was reduced at around -250 mV (Pt2+/Pt-0), in t he temperature range 800 degrees C-1000 degrees C, From the results of cycl ic voltammogram, it is suggested that in the system of 50 PbO . 50 SiO2 dis solving Pt, the reaction rate of reduction of Pt ion is much higher than th at of oxidation and the rate of electron transfer at electrode surface is s lower than ion diffusion. It was found that the electron transfer number of platinum ion is 2, meaning that platinum ion is dissolved as Pt2+ and the reaction on the electrode is Pt2+ + 2e(-)-->Pt-0. Various parameters such a s the diffusion coefficient and the reaction rate were determined for the m elt in which high concentration of platinum was disolved.