Ultrathin PtNiM (M = Rh, Os, and Ir) Nanowires as Efficient Fuel Oxidation Electrocatalytic Materials.

ABSTRACT

The development of new electrocatalysts with high activity and durability for alcohol oxidation is an emerging need of direct alcohol fuel cells. However, the commonly used Pt-based catalysts still exhibit drawbacks including limited catalytic activity, high overpotential, and severe CO poisoning. Here a general approach is reported for preparing ultrathin PtNiM (M = Rh, Os, and Ir) nanowires (NWs) with excellent anti-CO-poisoning ability and high activity. Owing to their superior nanostructure and optimal electronic interaction, the ultrathin PtNiM NWs show enhanced electrocatalytic performance for both methanol oxidation reaction (MOR) and ethanol oxidation reaction (EOR). The optimal PtNiRh NWs show mass activity of 1.72 A mg-1 and specific activity of 2.49 mA cm-2 for MOR, which are 3.17 and 2.79 times higher than those of Pt/C. In particular, the onset potentials of PtNiRh NWs for MOR and EOR shift down by about 65 and 85 mV compared with those of Pt/C. Density functional theory calculations further verify their high antipoison properties for MOR and EOR from both an electronic and energetic perspective. Facilitated by the introduction of Rh and Ni, the stable pinning of the Pt 5d band associated with electron-rich and depletion centers solves the dilemma between reactivity and anti-CO poisoning.