Investigation of Carbon Corrosion in Acidic Media through In Situ TEM and FTIR

As the core component in proton exchange membrane fuel cells, carbon corrosion is one of the main issues that can cause cell performance degradation. In situ analysis of carbon corrosion with high spatial and temporal resolution is helpful to reveal the mechanism and influencing factors of carbon corrosion and provides guidance for catalyst optimization. Herein, we investigate the carbon corrosion process by in situ transmission electron microscopy (TEM) and other characterization methods. The microstructure evolution and molecular scale reaction mechanisms of carbon corrosion have been analyzed. Carbon corrosion is extremely severe when exposed to a high potential (1< E < 1.5 V versus RHE). At the high potential, carbon undergoes incomplete oxidation and forms numerous oxygen-containing functional groups, which improves the hydrophilicity of the carbon surface. In this case, the pore distribution changes with corrosion of carbon and the destruction of the carbon microstructure causes the expansion of volume. Through the comparison experiment of hollow carbon spheres and carbon black XC-72, it is found that the observed volume expansion can be greatly alleviated with the increase in graphitization. This provides new visual understanding of why highly graphitized carbon has higher durability.