Impact of CuFe bimetallic core on the electrocatalytic activity and stability of Pt shell for oxygen reduction reaction

Abstract

Core-shell structure has been well recognized as a promising strategy to improve the catalytic efficiency for oxygen reduction reaction (ORR). Herein, we prepared a series of CuxFey@Pt/C core-shell catalysts with different core composition ratios based on seed-mediated growth method. Adding Fe atoms with smaller radius to the Cu core can tune the lattice strain and electronic structure of Pt shell, which can further improve the catalytic performance of the catalyst for ORR. Electrochemical tests show that the mass activity of Cu0·75Fe0.25@Pt/C catalyst is 0.91 A/mgPt, which is almost six times as high as that of commercial Johnson Matthey Pt/C catalyst. Furthermore, the Cu0·75Fe0.25@Pt/C catalyst exhibited high durability both in half-cell and single-cell tests. The superior activity and durability are attributed to the strain effect and ligand effect between CuFe alloy core and Pt shell. This work provides a strategy to design a core-shell structure catalyst with a non-precious alloy as its core and improve catalytic activity for ORR by regulating the core composition ratio.