Abstract: WC/TiO₂ precursor was fabricated by ball-milling a mixture of titania and ammonium metatungstate, then WC/TiO₂ nanocomposites were obtained after carbonization under CH₄/H₂ atmosphere at 900℃. The as-prepared samples were characterized by XRD, SEM, HRTEM, STEM and EDX, and their electrocatalytic activities were measured by microelectrode approach with three electrodes in basic solution. The results show that the crystal phase of tungsten species in the samples changes according to the following order: WO₃ →WO₂→W→W₂C or WC in the carbonization process. The tungsten carbide nanoparticles, which are decorated on the surface of titania, generally have a diameter less than 20 nm. The sample carbonized for 6h mainly have two catalytic active phases of very small size, namely WC and W₂C, which are uniformly dispersed on the surface of TiO₂ particles. The electrocatalytic measurement shows the sample is most active.

Key words: tungsten carbide, titania, nanocomposite, microstructure characterization