Electrochemical Characterization of IrO 2 -Pt and RuO 2 -Pt Mixtures as Bifunctional Electrodes for Unitized Regenerative Fuel Cells

Abstract

Unitized Regenerative fuel Cell (URFC) is an attractive and efficient method for producing hydrogen and clean energy. Nevertheless, to combine a polymer electrolyte water electrolyzer (PEMWE) and a polymer electrolyte fuel cell (PEMFC) is still a big challenge. Here, it is necessary to overcome several practical and structural features. For instance, the oxygen reduction (ORR) and the water oxidation (OER) are the limiting reaction steps at the oxygen electrode for PEMFC or PEMWE, respectively. Therefore, its high-efficiency depends on the type of electrocatalysts and the capability of the oxygen electrode to operate under the PEMFC or PEMWE conditions. As a consequence, a broad research is focused on developing a new design for the oxygen electrode in URFCs. In this work, several bifunctional electrodes for OER and ORR were designed by mixing electrocatalysts of Pt and IrO2 or Pt and RuO2 supported on Ebonex®. Elec- trochemical characterization by CV, LV and EIS in aqueous 0.5 M H2SO4 reveals that IrO2-Pt and RuO2-Pt supported on Ebonex®, exhibit high electrocatalytic properties for ORR and OER showing up a possible use in URFCs. In addition, IrO2 based electrodes display a higher stability than those based on RuO2.