In-Situ Monitoring of Preferential Dissolution of Pt-50at.% Fe Alloy under Potential Cycling in 0.5 M H2SO4 Solution Using a Channel Flow Triple Electrode

A channel flow triple electrode (CFTE) was employed for the in-situ detection of Fe2+ and Fe3+ preferentially dissolved from a Pt-50at.%Fe alloy under potential cycles in a 0.5 M H2SO4 solution. The CFTE consisted of a Pt-50at.%Fe alloy working electrode (PtFe-WE) and two split Au collector electrodes (Au-CE) placed upstream and downstream in a channel, respectively. The optimum potentials for detecting Fe2+ and Fe3+ on the Au-CEs were determined to be 1.0 and 0 V vs. a standard hydrogen electrode, respectively, when using solutions of different concentrations of FeSO4 and Fe-2(SO4)(3). When PtFe-WE was potential-cycled between 0.05 and 1.4 V, Fe dissolved as Fe2+ between 0.25 and 0.75 V in both anodic and cathodic scans, and mainly dissolved as Fe3+ above 1.1 V and from 0.9 to 0.5 V in cathodic scans. (C) 2016 The Electrochemical Society. All rights reserved.