Accelerated degradation of Pt-coated Ti porous transport layers under dynamic potential pulses in PEMWEs†

Abstract

Proton exchange membrane water electrolyzers are vital for sustainable hydrogen production, but a lack of understanding of their durability under potential perturbation presents a significant challenge. This study investigates the degradation behavior of Pt-coated Ti-based porous transport layers (PTLs) under dynamic potential pulses, mimicking potential perturbation. Using a three-electrode system, anodic potential pulses alternating with open-circuit voltage are applied to the PTL, revealing severe degradation compared to constant potential application. The pulsed potential accelerates Pt dissolution through repeated electrochemical and chemical reactions, forming oxidized Pt species and causing coating detachment. Physicochemical analyses confirm increased Pt oxide formation and substantial coating layer desorption under pulsed conditions, resulting in a significant drop in electrical conductivity. PEMWE full-cell tests demonstrate that degraded PTLs led to increased overpotentials and reduced cell performance. This study highlights the critical impact of fluctuating potential on PTL durability, providing insights into enhancing the stability and performance of the water electrolyzer.