Highly stable and active Pt-skinned octahedral PtCu/C for oxygen reduction reaction

Morphology-controlled Pt-based catalysts were synthesized by a solvothermal method and were used as oxygen reduction reaction (ORR) catalysts in proton exchange membrane fuel cells (PEMFCs). A mild acid treatment combined with electrochemical de-alloying was used to develop Pt-skinned octahedral PtCu/C-X catalysts. PtCu/C exhibited a mass activity (MA) of 0.694 A mgPt−1 @ 0.9 V and specific activity (SA) of 2.242 mA cm−2, respectively. After 30,000 potential cycles, the MA and SA of this catalyst were enhanced by 22% to 0.849 A mgPt−1 and 110% to 4.697 mA cm−2, respectively. It is hypothesized that the rearrangement of surface Pt atoms in electrochemical de-alloying effectively filled the defects formed by acid treatment and enhanced the activity of the catalyst accordingly.