Enhancing the Bifunctional Oxygen Evolution and Hydrogen Oxidation Properties of Nb-Doped SnO2-Supported IrO x Catalysts through Trace Pt Incorporation for PEM Water Electrolysis

Introducing hydrogen oxidation reaction (HOR) activity at the anode is considered a promising strategy for the oxidative removal of crossover hydrogen in proton exchange membrane water electrolysis (PEMWE), which may contribute to improved operational safety. In this study, Pt-incorporated IrOx catalysts supported on Nb-doped SnO2 (IrOx/Nb-SnO2) were investigated as bifunctional electrocatalysts with oxygen evolution reaction (OER) and HOR activities. Electrochemical evaluation using rotating disk electrode (RDE) measurements revealed that slight Pt incorporation (∼10 atom%) maintained high OER activity while introducing appreciable HOR activity. In contrast, excessive Pt incorporation enhanced HOR activity but significantly decreased OER performance, primarily due to the dilution of active Ir sites. These results demonstrate that trace Pt incorporation can effectively introduce HOR functionality while retaining high OER activity in IrOx-based catalysts, providing a potential strategy for the development of multifunctional anode electrocatalysts for PEMWE.