Mechanism study of adenine functionalized graphene oxide on proton transport efficiency and membrane property

Efficient proton transport is crucial for proton exchange membranes (PEMs) in the development process of fuel cells. In this work, adenine-modified graphene oxide was successfully synthesized (AGO) and then introduced as the filler into the sulfonated poly (aryl ether ketone sulfone) containing carboxyl groups (C-SPAEKS) polymer matrix for the preparation of composite PEMs. The highly hydrophilic groups (Carboxy and hydroxy groups) on the surface of graphene oxide nanosheets and N heterocycles of adenine play a synergistic enhancement role in providing proton transport sites and constructing proton transport channels. The C-SPAEKS-0.5 %-AGO composite membrane which means the AGO content was 0.5 wt% had the highest proton conductivity of 201.54 mS cm −1 at 90°C and a tensile strength of 43.93 MPa. In addition, the current density of 2005 mA cm −2 corresponded to a peak density of 791.53 mW cm −2 of C-SPAEKS-0.5 %-AGO, which was 3.4 times of that of the pure membrane (231.83 mW cm −2 ). The results showed that the adenine-modified graphene oxide significantly improves the electrochemical performance of the PEMs.