Chemical degradation of Nafion ionomer at a catalyst interface of polymer electrolyte fuel cell by hydrogen and oxygen feeding in the anode

► Degradation on Pt/Nafion is investigated by feeding H2 and O2 in anode side of PEFC. ► Generated solution has HF 5.0 × 10− 6 mol·l− 1 of HF, slightly small number as product of degradation. ► Using DFT to study the dissociation of trifluoromethanesulfonate (TFMS) as a Nafion model ► H and OH radicals induce the degradation of TFMS and formation of HF, CF2O and SO3H. ► The degradation of TFMS is affected not only by BDE but also by the behavior of fluorine.