Multifunctional Pt-CeO2-CNT composite membranes for high-performance PEM water electrolysis with reduced H2 permeation and enhanced chemical durability

Abstract

Proton exchange membrane (PEM) water electrolysis efficiency can be significantly enhanced by reducing the membrane thickness; however, this approach leads to excessive H₂ permeation into O₂ (HiO), causing serious safety hazards and accelerated degradation. This study presents a novel thin (about 60 μm) composite membrane incorporating Pt and CeO₂ nanoparticles supported on carbon nanotubes (Pt-CeO₂-CNT/Nafion) to address these challenges. The catalysts embedded in the membrane exhibit synergistic multifunctional effects at the microscopic level. CeO₂ transfers electrons to Pt through metal–support interactions, enhancing the H₂–O₂ recombination activity. Oxygen vacancies in CeO₂ effectively scavenge free radicals (H˙, HO₂˙, HO˙, etc.). CNTs serve as stable anchoring sites, preventing Ce^δ+ migration and membrane poisoning. At the macroscopic level, Pt-CeO₂-CNT/Nafion maintains superior electrochemical performance with an electrolysis voltage of 1.746 V at 3.0 A cm⁻². Meanwhile, the HiO concentration remains below 0.7% across all tested current densities, and the F⁻ release rate decreases by 3.8-fold compared to Pt-CNT/Nafion during long-term operation, indicating improved safety and durability. This work provides both fundamental insights and practical strategies for developing next-generation thin PEMs suitable for industrial applications.