Application of X-ray photoelectron spectroscopy to studies of electrodes in fuel cells and electrolyzers

The activity and stability of catalysts used in anodes and cathodes in fuel cells and electrolyzers is a vital factor for practical industrial applications. To improve performance characteristics, it is essential to link the structure and composition of the catalyst on the electrodes to electrochemical performance and durability. The investigation of the durability of materials for application in fuel cells and electrolyzers is a particularly important task. Application of x-ray photoelectron spectroscopy (XPS) to probing the chemistry of catalyst layers and their degradation is becoming a central analytical approach due to quantitative chemical information it provides. Herein we present several cases of application of high-resolution XPS for analysis of the chemistry of electrodes and changes that are occurring during operation in several technological platforms, such as proton-exchange membrane fuel cells (PEMFCs), alkaline membrane fuel cells (AEMFC), direct methanol fuel cells (DMFC), direct hydrazine fuel cells (DHFC) and water electrolyzers (WE). Challenges of analyzing surface chemistry of electrodes and approaches to address them are discussed.