Microfluidic in operando investigation of platinum transport in proton exchange membranes for electrolyzers and fuel cells

• Applicant: Dr.-Ing. Sebastian Brosch
• Subject Area: Chemical and Thermal Process Engineering
• Term: since 2026
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 584721313

Proton exchange membrane water electrolyzers (PEMWEs) and fuel cells (PEMFCs) are key technologies for a sustainable hydrogen economy. However, their long-term stability is limited by degradation of the catalyst layers and subsequent inhibition of proton transport within the proton exchange membrane (PEM). Dissolution and migration of platinum species from the catalyst into the membrane reduce the electrochemically active surface area and impair proton transport, yet the underlying transport mechanisms remain poorly understood, especially under transient and in operando conditions. At the same time, increasing environmental concern and regulatory pressure on fluorinated polymers motivates the development of fluorine-free, hydrocarbon-based PEMs, whose transport properties are largely unexplored. This project aims to establish a mechanistic understanding of coupled water, proton, and platinum ion transport in proton exchange membranes and to identify membrane properties that suppress catalyst degradation. To this end, a microfluidic platform will be developed comprising of proton exchange membranes and porous electrodes to enable simultaneous electrochemical operation and optical characterization. Using fluorescence microscopy with water- and platinum-sensitive dyes, transient hydration dynamics and platinum ion mobility will be quantified directly within the membrane under realistic operating conditions. Initial studies will focus on water transport and interfacial hydration in benchmark perfluorosulfonic acid membranes, followed by systematic investigations of state-of-the-art hydrocarbon membranes. Platinum transport will be probed using synthesized platinum-responsive fluorescent sensors, first in idealized interdigitated electrode geometries and subsequently in fully integrated microfluidic electrolyzer and fuel cell configurations under accelerated stress conditions. Complementary electrochemical measurements will in operando validate performance and degradation behavior. Finally, proton transport and electroosmotic drag will be quantified using fluorescence lifetime imaging microscopy, enabling the development of a holistic transport model that links hydration, ion mobility, and catalyst degradation. The project will provide fundamental insights into membrane-controlled catalyst stability and establish microfluidic operando methodologies applicable to a broad range of electrochemical energy technologies.

• DFG Programme: Fellowship
• International Connection: Canada
• Host: Professorin Dr. Anne Benneker