Microstructure Characterization and Electrocatalytic Properties of WC/TiO2 Nanocomposites

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/H-2 atmosphere at 900 degrees C. 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.