Constructing an ultra-low loading of IrPt bimetallic coated porous transport layer (PTL) for a PEM water electrolyzer application

The passivation of Ti-based porous transport layer (PTL) occurs due to the formation of TiO x during prolonged operation of the proton exchange membrane water electrolyzer (PEMWE) in an acidic environment, thereby increasing the cell voltage. In this study, a bimetallic coating of Ir and Pt was applied using the sputtering technique to mitigate the degradation of Ti-based PTLs. The bimetallic coating not only minimized the precious metal loading to ultra-low levels but also demonstrated exceptional anti-corrosive properties. The stability number was employed to study about the dissolution behavior of precious metals, enabling direct evaluation of their lifetime. The bimetallic coated (IrPt-0.08) PTL exhibited 5.8, and 135.8-times higher stability number than those of the single metal Pt, and Ir, respectively. The Ir 4+ content in the bimetallic coating increased slightly compared to the single-metal Ir coating, which contributed to enhanced charge transfer against corrosion in acidic media. Using the IrPt-0.08 PTL, a single-cell performance of 1.730 V at 2.0 A cm −2 was achieved at 80 °C under ambient pressure. The bimetallic coating enhanced the conductive area in contact with the catalyst layer, facilitating the efficient charge transfer at the catalyst layer/PTL interface, furthermore, offered a durable PTL for the PEMWE applications. • Development of ulta-low loading IrPt bimetallic coatings on the Ti PTL. • Stability number was employed to investigate dissolution behaviour of coatings. • Conducted the comprehensive in-situ and ex-situ characterizations. • IrPt-coating showed better anti-corrosive properties compared to single metal Ir, Pt. • IrPt bimetallic coated Ti PTL offered PEMWE performance of 1.73 V at 2 A/cm 2 .