Vertically Aligned and Surface Roughed Pt Nanostructured Wire Array as High Performance Electrocatalysts for Methanol Oxidation

Abstract

In this research, an enhanced electrocatalyst based on vertically aligned and surface roughened Pt nanostructured wire arrays (Pt NWAs) has been developed. Our results showed that Pt NWAs possessed extremely high electrochemical performance and efficiency toward methanol oxidation. The three-dimensional nanostructured wire array electrode was prepared with electrodeposition method using anodic aluminum oxide (AAO) membrane on silver substrate, after which the active array electrode was obtained by dissolving the AAO templates. Varying the electrodeposition current density and synthesis time led to the controlled length and surface roughness of the Pt nanostructured wires. Scanning electron microcopy, energy dispersive X-ray spectroscopy, and X-ray powder diffraction were employed to characterize the morphology, composition, and crystal structure of the nanostructured wires. Cyclic voltammetry (CV) and chronoamperometry were used to analyze the performance and endurance of the wire array electrode. Electrochemical impedance spectroscopy measurements provided insights in the electron transfer resistance between the electrode and analyte. Gas chromatography (GC) and UV–vis spectroscopy were carried out to identify the presence of the possible products and the relative concentration change of methanol vs the numbers of cyclic voltammetry scanning. The electrochemical measurements showed only one dominant forward anodic peak and the absence of backward anodic peak. GC results showed that methanol concentration decreased linearly with the CV scanning cycles, and a negligible amount of side products were detected, suggesting a complete methanol oxidation. This prepared electrode exhibited high electrochemical activity, high endurance, and low electron transfer resistance.