How Good is Graphene Carbon as a Fuel Cell Catalyst Support?

Graphene-based carbon supports have been widely researched in the fuel cell community due to their interesting morphology, microstructure, and surface chemistry. In this study, the scope of graphene carbon's practical use as a support material for PtCo cathode catalyst was evaluated in detail. Graphene support has favorable oxygen transport characteristics due to its sheet like morphology thereby enabling a superior beginning-of-life performance compared to that of state-of-art KetjenBlack (TM) type high surface area carbon (HSC). Further, significant hydrophilicity due to higher water uptake by graphene surface functional groups enables 30% lower ionomer usage in the electrode. However, the durability of PtCo/Graphene is lower compared to that of PtCo/HSC carbon support especially at current densities < 2 A cm(-2) due to increased Pt catalyst coarsening on the sheet-like graphene carbon and possible restacking of graphene sheets. Efforts were made to improve the durability of PtCo/Graphene catalyst layers via dilution with HSC support but only with modest success. Unlike the several publications in the literature that discuss the benefits of graphene carbon support, this article highlights the significant durability improvements needed to enable PtCo/Graphene as a viable cathode in fuel cell applications.