Monitoring of anodic corrosion on carbon-based gas diffusion layer in a flow cell

Due to the recent increase in carbon-based gas diffusion layer (GDL) usage for high-rate electrochemical reactors, the study on mitigating anodic corrosion associated with the GDL is imperative. In this study, the anodic corrosion of a high-rate electrochemical flow cell was evaluated using an on-line universal gas chromatography protocol with iridium oxide supported GDL (IrO2/GDL) as a model electrode, and it could be evidently alleviated in the alkaline media (1 M KOH) with an inert gas (Ar or N2) environment within current densities of 500 mA cm-2. In addition, the quantitative CO2/CO formation rate and Faradaic efficiencies results, along with the qualitative hydrophobicity maintenance ability of the anode, revealed that the anodic oxidation reaction could be efficiently suppressed in the carbon support samples with both high graphitization and good oxygen evolution reaction (OER) activity, such as the multi-walled carbon nanotubes. Therefore, further modification of the carbon-based GDL itself may help to prevent its corrosion above 500 mA cm-2. This work is important for tracing the origin of electrocatalysis deactivation and directing the design of carbon materials for the future electrodes that involving the GDL on a high-rate electrochemical reactor.