Synthesis of Ultrafine Mesoporous Tungsten Carbide by High-energy Ball Milling and Its Electrocatalytic Activity for Methanol Oxidation

摘要

Ultrafine mesoporous tungsten carbide (WC) was prepared from as-synthesized mesoporous WC using high-energy ball milling treatment. X-ray diffraction (XRD), scanning electron microscopy (SEM), and nitrogen adsorption-desorption techniques were used to characterize the samples. Brunauer-Emmett-Teller (BET) surface areas of WC samples increased with the increasing ball milling time and kept constant at 10-11 m2·g-1 for over 9h. The electrocatalytic properties of methanol electro-oxidation at WC powder microelectrodes were investigated by cyclic voltammetry, chronoamperometry, and quasi-steady-state polarization techniques. The results reveal that ball-milled WC exhibits higher activity for methanol electro-oxidation than as-synthesized mesoporous WC. The suitability of ball-milled WC for methanol electro-oxidation is better than platinum (Pt) micro-disk, although the current peak is not as high as the Pt micro-disk. Moreover, increasing the methanol concentration and reaction temperature promotes methanol electro-oxidation on ultrafine mesoporous WC.