Electrosprayed catalyst layers based on graphene–carbon black hybrids for the next-generation fuel cell electrodes

Here, we report a novel electrode structure with graphene and graphene–carbon black hybrids by electrospraying for polymer electrolyte membrane fuel cells. After syntheses of platinum (Pt)/partially reduced graphene oxide (rGO) and Pt/r-GO/carbon black (CB) hybrid electrocatalysts, suspensions of synthesized electrocatalyst inks were prepared with Nafion^® ionomer and poly(vinylidene fluoride-co-hexafluoropropylene) and electrosprayed over carbon paper to form electrodes. Electrosprayed catalyst layer exhibited uniform and small size Pt distribution. As the graphene content increases micrometer-sized droplet, pore formation and surface roughness of the electrode increase. Thus, an open porous electrode structure which is favorable for mass transport is achieved by electrospraying. The maximum power densities, 324 mW cm⁻² for Pt/rGO and 441 mW cm⁻² for Pt/rGO/CB electrosprayed electrodes, were achieved at a relatively low catalyst loading.