Oxygen　reduction　reaction　(ORR)　activity　and　durability　of　Pt　catalysts　should　be　both　valued　for　successful　commercialization　of　proton　exchange　membrane　fuel　cells　(PEMFCs).　We　offer　a　facile　one-pot　synthesis　method　to　prepare　Pt/CeO2/C　composite　catalysts.　CeO2　nanoparticles,　with　high　Ce3+　concentration　ranging　from　30.9%　to　50.6%,　offers　the　very　defective　surface　where　Pt　nanoparticles　preferentially　nuclear　and　growth.　The　Pt　nanoparticles　are　observed　sitting　on　the　CeO2　surface,　increasing　the　Pt[sbnd]CeO2　interface.　The　high　concentration　of　oxygen　vacancies　on　CeO2　surface　and　large　Pt[sbnd]CeO2　interface　lead　to　the　strong　Pt[sbnd]CeO2　interaction,　effectively　improving　the　ORR　activity　and　durability.　The　mass　activity　is　increased　by　up　to　50%,　from　36.44 mA mg−1　of　Pt/C　to　52.09 mA mg−1　of　Pt/CeO2/C　containing　20 wt.%　CeO2.　Pt/CeO2/C　composite　catalysts　containing　10–30 wt.%　CeO2　loss　about　80%　electrochemical　surface　area　after　10,000　cycles,　which　is　a　fivefold　enhancement　in　durability,　compared　to　Pt/C　losing　79%　electrochemical　surface　area　after　2000　cycles.　©　2017　Hydrogen　Energy　Publications　LLC