(42ab) Constructing Ultrathin, Methanol Sieving Graphene Oxide Layer on Nafion Membrane for Direct Methanol Fuel Cells

Perfluorosulfonic polymers such as Nafion are the most common membrane electrolytes used in polymer electrolyte and direct methanol fuel cells (PEFCs and DMFCs) owing to their high proton conductivity and good chemical and thermal stability. However, methanol readily migrates from the anode, through the Nafion membrane, to the cathode, considerably reducing the open-circuit potential and poisoning the electrocatalysts at the cathode. Sieving methanol with proton by constructing a thin separation layer on Nafion is an idea strategy to solve this proplem. In this study, we aim to precisely sieving methanol/proton by constructing an ultrathin sulfonated graphene oxide (GO) membrane on Nafion. Through adjusting graphene oxide spacing, an exceptionally high selectivity is obtained. This high selectivity is due to the GO membrane having selective nanochannels which can block the transport of methanol and permit the transport of proton.