Experimental Methodologies to Understand Degradation of Nanostructured Electrocatalysts for PEM Fuel Cells: Advances and Opportunities

The development and application of advanced experimental tools is a major driving force in modern electrocatalysis. This is particularly true for stability studies with nanostructured oxygen reduction reaction electrocatalysts for PEM fuel cells. Indeed, our understanding of the catalyst degradation mechanisms could not have been achieved without the arsenal of analytical tools developed over the last decades. This contribution aims at highlighting the value of such a multi‐faceted analytical toolbox. Several classes are examined: from techniques applied for dissolution studies with bulk electrodes, to ex situ and in situ investigations with model high‐surface‐area catalysts. Finally, electrochemical and imaging methods employed to characterize catalyst layers are presented. The respective features, advantages, problems and possible future developments are discussed.