Surface unsaturated WOx activating PtNi alloy nanowires for oxygen reduction reaction.

This work achieves an effective regulation of the ORR activity and stability for PtNi alloy nanowires by the synergistic effect of WO x on Pt. [Display omitted] • The ORR activity of WO x -PtNi NWs shows a volcano trend with W content. • Synergistic effect of WO x on Pt can accelerate the ORR kinetics. • WO x with unsaturated coordination can stabilize the surface atoms of PtNi alloy NWs. PtNi alloy nanoparticles display promising catalytic activity for oxygen reduction reaction (ORR), while the Ostwald ripening of particles and the dissolution/migration of surface atoms greatly affect its stability thus restricting the application. Herein, the WO x -surface modified PtNi alloy nanowires (WO x -PtNi NWs) exhibiting enhanced ORR catalytic property is reported, which has high aspect ratio with the diameter of only 2 ∼ 3 nm. It is found that the WO x -PtNi NWs shows a volcano relationship between the ORR activity and the content of WO x. The WO x-(0.25) -PtNi NWs has the best performance among all the synthesized catalysts. Its mass activity (0.85 A mg−1 Pt) is reduced by only 23.89% after 30k cycles durability test, which is much more stable than that of PtNi NWs (0.33 A mg−1 Pt , 45.94%) and Pt/C (0.14 A mg−1 Pt , 57.79%). Hence this work achieves an effective regulation of the ORR activity for PtNi alloy NWs by the synergistic effect of WO x on Pt. [ABSTRACT FROM AUTHOR]