Observation of the surface morphology of carbon alloy catalysts in aqueous solution by atomic force microscopy

Abstract

Carbon alloy (CA) catalysts have emerged as a promising class of nonplatinum electrocatalysts for polymer electrolyte fuel cells. A comprehensive understanding of their catalytic degradation mechanisms is crucial for improving the performance of these cells. This study uses a novel film-based CA model catalyst that facilitates in situ observations in acidic solutions using atomic force microscopy (AFM) to elucidate these degradation mechanisms. The findings reveal significant structural alterations in the nanoshell structure from a closed shell to the floppy configuration of CA catalysts under aqueous conditions (water and H₂SO₄ solution). These changes are undetectable by scanning electron microscopy. AFM analysis confirmed that oxidation-induced degradation leads to structural alterations and the subsequent loss of the structure of the carbon, which may be an important finding for improving the stability and performance of CA catalysts.