A Facile and Sustainable Enhancement of Anti‐Oxidation Stability of Nafion Membrane

Abstract

• OH radicals are the main cause of chemical degradation of Nafion membranes in fuel cell operation. Although the cerium ion (Ce3+/4+, Ce) is reported as an effective•OH radical quencher, its membrane application has critical limitations associated with the reduction of membrane proton conductivity and its leaking. In this study, the Ce‐grafted graphitic carbon nitrides (g‐C3N4) (CNCe) nano‐particles are synthesized and embedded in Nafion membranes to prolong the• OH radical scavenging effect. The synthesis of CNCe nano‐particles is evaluated by X‐ray diffraction, energy dispersive X‐ray analysis, and transmission electron microscopy. Compared with the pristine and Ce‐blended Nafion membranes, the CNCe imbedded ones show tremendous improvement in long-term anti‐oxidation stability. While the fluoride emission rates of Nafion are 0.0062 mg∙cm−2∙h−1 at the anode and 0.0034 mg∙cm−2∙h−1 at the cathode, those of Nafion/CNCe membranes are 0.0037 mg∙cm−2∙h−1 at the anode and 0.0023 mg∙cm−2∙h−1 at the cathode. The single cell test for Nafion/CNCe membranes at 80 °C and 50% relative humidity illustrates much better durability than those for Nafion and Nafion/Ce, indicating its superior scavenging effect on• OH radicals.