A novel core-shell nanostructure of Ti-Au nanocrystal with PtNi alloy skin: Enhancing the durability for oxygen reduction reaction

The sluggish oxygen reduction reaction (ORR) at the cathode largely hinders the practical application of the proton-exchange membrane fuel cells (PEMFCs). Pt-based nanocrystals are the most effective electrocatalysts for the oxygen reduction reaction, however, suffer high cost, scarcity and unsatisfied durability. Herein, we report a new category of annealed multimetallic core-shell catalyst of gold core doped with titanium and platinum-nickel (PtNi) shell with Pt-rich surface as a highly active and robust electrocatalyst for ORR. The introduction of titanium can effectively stabilize the gold core, avoiding the outward migration of Au atoms and ensuring the exposure of Pt-Ni active sites. The experimental findings revealed that the annealed Ti-Au@PtNi NPs catalyst provides 19.26 and 9.84 times higher mass and specific activities than commercial Pt/C catalysts for the oxygen reduction reaction. Moreover, durability tests of annealed Ti-Au@PtNi NPs show no noticeable activity loss even after 20000 potential cycles between 0.6 and 1.0 V vs. RHE, demonstrating a promising catalyst for the oxygen reduction reaction.