Nanohybrids of graphene oxide chemically-bonded with Nafion: Preparation and application for proton exchange membrane fuel cells

Electrospinning preparation of a graphene oxide nanohybrid proton‐exchange membrane for fuel cells

“…These values are much higher than those of recast Nafion membranes mentioned (e.g., 50%–60% in Ref. ) in previous literature . This can be attributed to the increased sensitivity of Nafion in nanofiber form to humidity .…”

“…Furthermore, the observed proton conductivity of 0.1% GO/Nafion fiber membrane of 0.079 S/cm at 80 °C (see Table ), which is characteristic for our electrospinning preparation method, is large compared with the values reported in the literature (e.g., 0.065 S/cm in Ref. ). This phenomenon can be explained in two ways: The excellent water retention properties of nanofibers promote the formation of continuous hydrophilic channels with interconnected ionic clusters; a one‐dimensional long‐range ion transport channel can be constructed with nanofibers, to achieve relatively high proton conductivity …”

“…At 910–1450 cm −1 , it was the vibration bands of sulfonic acid group, corresponding to SO and SOH characteristic peaks. Furthermore, the peaks at 1221 and 1153 cm −1 were the characteristics of the framework of perfluorinated sulfonic acid and sulfonic acid groups overlapped with the peaks . Similarly, in the case of the GO/Nafion fiber mats, no new peaks were observed for the composite membranes, indicating that no significant chemical bonds were formed between the incorporated GO and Nafion.…”

“…The proton conductivity of 0.1% GO/Nafion fiber membrane was approximately 1.4 times that of the Nafion fiber membrane, which was because Nafion chains bonded on the surfaces of GO nanosheets could promote the aggregation of Nafion chain to form continuously ionic clusters . The original three‐dimensional proton transfer channel was transformed to an ordered two‐dimensional channel.…”

“…Moreover, amphipathic GO can interact with the hydrophobic main chain of Nafion and the hydrophilic sulfonic groups of side chains after being added to the Nafion matrix reduce the phase separation in the presence of water molecules, and thus improve the penetration ability of the GO‐based nanohybrid Nafion membrane . Moreover, the doping of GO promotes the building of two‐dimensional ionic channels with the oxygen groups of GO and sulfonic acid of Nafion or water molecules, which form a hydrogen bond network in the matrix, which is beneficial to the proton transport owing to the “hopping” mechanism . However, excessive incorporation of GO may lead to the decline of proton conductivity owing to the deficiency of sulfonic acid density and the blocking effect .…”