Performance of nano-nickel core wrapped with Pt crystalline thin film for methanol electro-oxidation

Abstract

Ni@Pt core–shell nanoparticles with Pt nanocrystal thin film are synthesized by chemical reduction to investigate methanol oxidation. The morphology, structure, and composition of the as-prepared nanoparticles are characterized by aberration-corrected high-resolution transmission electron microscopy, X-ray diffraction, energy dispersive spectroscopy, and X-ray photoelectron spectroscopy. Electrochemical characterizations are performed by cyclic voltammetry, in situ Fourier transform infrared spectroscopy, and chronoamperometry. Results show that the as-prepared nanoparticles have a core–shell nanostructure. Moreover, Pt on the shell is composed of small clusters that are poorly crystalline domains of different crystal faces. The Pt mass activity of the as-prepared nanoparticles is about three times that of conventional E-TEK 40 wt% Pt/C catalysts, and methanol oxidation over the as-prepared nanoparticles is found to occur at a lower overpotential than over Pt/C. The as-prepared nanoparticles also exhibit markedly high resistance to carbon monoxide deactivation. This high electrocatalytic performance can be attributed to the unique structure of the as-prepared nanoparticles.