The degradation mitigation effect of cerium oxide in polymer electrolyte membranes in extended fuel cell durability tests

► Ceria nanoparticles incorporated into polymer electrolyte fuel cell membranes. ► Ceria decreases open-circuit voltage decay and fluoride emission in 94 h tests. ► Ceria decreases platinum deposition and broadens platinum band. ► Ceria remains effective over 500 h, resulting in almost no membrane degradation.