Mo-doped PdCu nanoparticles as high-performance catalysts for oxygen reduction reactions.

ABSTRACT

The instability of palladium-based binary alloys hinders their wide application in the oxygen reduction processes. Here, we prepared Mo-doped PdCu nanoparticles with controllable dopant content and valence. Further research has revealed that Mo, particularly Mo5+, may effectively suppress the oxidation of Pd and Cu, optimize the oxygen binding of Pd, and increase catalytic activity and stability. In particular, Mo-PdCu-1/C with the highest Mo5+ content shows the best oxygen reduction reaction (ORR) mass activity (1.20 A mg-1Pd), which is 4.8 times higher than that of PdCu/C. It also exhibits outstanding stability, retaining 80.8% of the original mass activity after 20 000 cycles. This study clearly explains the mechanism by which Mo doping affects the performance and provides a reference for further optimization of catalyst performance for fuel cell industrialization.