以纳米TiO_2为载体,偏钨酸铵为钨源,采用机械化学法与原位还原碳化相结合的方法制备了碳化钨-TiO_2纳米复合材料,并用X射线衍射和扫描电子显微镜等手段对样品的晶相和形貌进行了表征.结果表明,样品颗粒为不规则粒状,并有不同程度的团聚,样品的晶相组成与还原碳化时间有关,主要有金红石相TiO_2,非化学计量比氧化钛(Ti_6O_(11)),W_2C,W_1C和未定名碳化钨.其中,TiO_2粒径18.8～95.6nm,W_2C粒径17.4～24.2 nm,W_1C粒径14.7～15.8 nm.在三电极体系中,采用循环伏安法测定了样品对对硝基苯酚的电催化活性.结果表明,样品的电催化活性与晶相组成有关,且W_1C与TiO_2构成复合材料后,两者之间存在明显的协同效应.这说明TiO_2是W_1C的良好载体.
A tungsten carbide-titania nanocomposite was fabricated by combining mechanochemical approach with reduction-carbonization technology using titania nanopowder as the support and using ammonium metatungstate as the tungsten precursor. The crystal phase, the diameter of crystallite, and the morphology of the sample were characterized by X-ray diffraction and scanning electron microscopy. The results showed that the morphology of the sample particles was of irregular granules with same congregations. The crystal phase of the sample was composed of rutile (TiO_2), nonstoichiometric ratio titania (Ti_6O_(11)), bitungsten carbide (W_2C), monotungsten carbide (W_1C), and unnamed tungsten carbide. The diameter of TiO_2 crystallites was 18.8-95.6 nm, that of W_2C was 17.4-24.2 nm, and that of W_1C was 14.7-15.8 nm. The electrocatalytic activity of the sample for p-nitrophenol was measured by cyclic voltammetry in acidic solution with a three-electrode system. The results indicated that the electrocatalytic activity of the sample was correlated to its crystal phases, and a syner-gistic effect existed between tungsten carbide and titania in the nanocomposite.
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