One-step phosphorylation of graphene oxide for the fabrication of nanocomposite membranes with enhanced proton conductivity for fuel cell applications

In this work, graphene oxide (GO) was phosphorylated by a novel method and then incorporated into the chitosan (CS) matrix for the fabrication of nanocomposite membranes with enhanced proton conductivity for fuel cell applications. The 2D phosphorylated graphene oxide (PGO) offers efficient proton hopping sites (–PO3H−···+H3N-) that form continuous proton conducting channels at the CS/PGO interface. The CS/PGO nanocomposite membrane containing 2 wt% of PGO shows an optimum proton conductivity of 0.036 S cm−1, which is higher than that of commercial Nafion 117 membrane (0.033 S cm−1). In comparison with CS control membrane, CS/PGO nanocomposite membranes have higher thermal and mechanical stability because of the strong electrostatic and hydrogen bonding interactions between –NH2 of CS and –PO3H2 of GO. This study provides a new facile way to fabricate high-performance, low-cost and eco-friendly nanocomposite membranes for fuel cell applications.