Pore-arrayed hydrogen molybdenum bronze: Preparation and performance as support of platinum nanoparticles for methanol oxidation

A novel electrocatalyst for methanol oxidation is fabricated by decorating platinum nanoparticles on pore-arrayed hydrogen molybdenum bronze (HxMoO3). In this fabrication, pore-arrayed HxMoO3 is prepared with polystyrene monolayer as a template, and platinum nanoparticles are decorated on the resulting pore-arrayed HxMoO3 by using a current pulse technique. The fabricated electrocatalyst is investigated with a combination of physical characterizations from X-ray diffraction, scanning electron microscopy and Fourier transform infrared spectroscopy, and electrochemical measurements including cyclic voltammetry, chronopotentiometry, chronoamperometry, and cell discharge test. It is found that the platinum decorated on pore-arrayed HxMoO3 (Pt/p-HxMoO3) is more uniform, has smaller particle size and exhibits improved electrocatalytic activity and stability for methanol oxidation, compared to that on non-pore-arrayed HxMoO3 (Pt/HxMoO3). The peak current for methanol oxidation in cyclic voltammetry is improved from 4.89 mA cm−2 for Pt/HxMoO3 to 6.41 mA cm−2 for Pt/p-HxMoO3, and the time for abrupt potential change in chronopotentiometry is enhanced from 498 min for Pt/HxMoO3 to 576 min for Pt/p-HxMoO3. The improved performance is attributed to the larger specific surface area of the pore-arrayed HxMoO3, which favors the formation of smaller Pt nanoparticles.