Core-shell Pt modified Pd/C as an active and durable electrocatalyst for the oxygen reduction reaction in PEMFCs

► Shell/core Pt/Pd/C catalysts are prepared by a facile chemical reduction method. ► Pt/Pd/C has better ORR activity and durability than that of Pt/C. ► Pd@Pt is converted to Pt-Pd alloy with Pt rich surface after potential cycling.