Real-time monitoring of electrochemical carbon corrosion in alkaline media

Carbon materials have been used as supporting substrates for electrocatalytically active species in many important reactions due to their high electrical conductivity and chemical inertness. To secure durable electrocatalysis, the fundamental understanding and prevention of corrosion are pivotal. The real-time monitoring of evolved CO 2 enabled by differential electrochemical mass spectroscopy (DEMS) has provided potential-resolved information about carbon corrosion. However, this approach is typically limited to acidic media and it is unavailable in alkaline media because of the carbonation of the CO 2 tracer. In this study, we investigate carbon corrosion using carbon monoxide (CO) as a corrosion marker. The electrochemical oxidation of selected model substrates ( i.e. , activated carbon, graphite, and Pt/C) is analyzed under dynamic and static potential excursions using DEMS. The results demonstrate that the CO tracer successfully monitored carbon corrosion in both acidic and alkaline media. The corrosion in alkaline media is qualitatively analogous to that in acidic media, but it is quantitatively alleviated, as confirmed by the decreased DEMS intensity and the decreased faradaic charge flowed. Carbon monoxide as a corrosion marker that enables real-time monitoring of electrochemical carbon corrosion in a wide range of electrolyte pH, even in neutral and alkaline media, where the typical carbon dioxide marker is transformed to (bi)carbonate anions.