High electrochemical activity from hybrid materials of electrospun tungsten oxide nanofibers and carbon black

Tungsten oxide (WO₃) nanofibers were prepared by oxidizing the electrospun ammonium metatungstate (AMT) and polyvinyl pyrrolidone (PVP) composite fibers. The WO₃ nanofibers with controllable diameters ranging from 80 to 130 nm were obtained by electrospinning different AMT/PVP mixture solutions. Electrochemical activity of the WO₃ nanofibers was measured in 0.5 M sulfuric acid solution. Cyclic voltammetry tests show that the WO₃ nanofibers have electrochemical activity which is closely related to hydrogen oxidation in fuel cells and the electrochemical activity could be greatly enhanced by the addition of carbon black. The hybrid materials of the WO₃ nanofibers and carbon black with the WO₃:C mass ratio of 10:1 possess high electrochemical activity with an anodic peak current density of 11.2 mA/cm², even higher than the commercial 20 wt% Pt/C catalyst. The electrospun WO₃ nanofibers may be promising electrocatalysts or catalyst supports for hydrogen oxidation in fuel cells due to the simplicity in production and high electrochemical activity.