Electrocatalytic performance of highly loaded PtNi intermetallic nanoparticles for oxygen reduction

PtNi/C disordered alloy nanoparticles, synthesized in ethylene glycol solution, were annealed and converted into ordered PtNi/C intermetallic nanoparticles. Such an ordered intermetallic PtNi/C catalyst showed enhanced specific activity and mass activity, which were about 2.3 and 1.66 times those of Pt/C for the oxygen reduction reaction (ORR), in comparison with the Pt/C catalyst. After accelerated stress tests (ASTs), the ORR mass activity of the Pt/C and PtNi/C intermetallic nanoparticles decreased to 88.92% and 36.95% of the initial values, respectively; and the mass activity of PtNi/C intermetallic nanoparticles after ASTs was equivalent to the initial one of the Pt/C catalyst. The enhanced ORR activity and durability of the PtNi/C intermetallic nanoparticles could be attributed to the ordered atomic configuration and the increased content of zero valence metal on the surface of nanoparticles. Moreover, the ordered PtNi/C intermetallic nanoparticles exhibited higher methanol tolerance during the ORR than the Pt/C catalyst.