| Tungsten carbide bears an analogy of the catalytic capability of noble metal, e.g.Pt, and higher ability to resist very strong catalytic poisons, but its catalytic activityis much lower than that of noble metal. How to improve its catalytic activity is oneof the difficult points and the hot topics in recent years. In order to find an approachto solve this problem, tungsten carbide/carbon tube nanocomposition was preparedthrough combination surface decoration with in situ reduction and carbonization.The samples were characterized by FTIR, XRD, EDS, SEM, TEM, HRTEM, andBET, respectively. Its electrocatalytic activity was tested by powder-microelectrodemainly.In the first chapter, the structure and preparation of WC, and the application ofcarbon nanotube were simply stated, and the in the second chapter, the experimentalprocess was introduced.In the third chapter, the preparation of tungsten carbide/carbon tube nanocomposite was investigated. Firstly, the raw carbon nanotube was modified in nitricacid solution, which reacting temperature is 150℃and reacting time is 4h. Secondly,ammonium metatungstate (AMT) was reacted with the modified carbon nanotubes toprepare CNT/WO3. The reacting temperature is 90℃and reacting time is 8h. At last,tungsten carbide/carbon tubes nanocomposite was prepared by a technique ofgas-solid reaction. The property and structure of tungsten carbide will be affected byits preparing conditions. The optimal coditions, as our experiments considered, ofthe sample preparation are: decomposition temperature 350～500℃, reactiontemperature 650～850℃, reaction pressure 8cm2 H2O, reaction time 7.5～12h.The results of XRD, EDS, SEM, TEM, and HRTEM show that the sample iscomposed of CNT, WC, WCx, W18O4, and the morphology of the particles oftungsten carbide is nanoscale irregular, with a diameter of samller than 30nm, andWC granules distribute on the surface of carbon nanotube homogenously.In the forth chapter, the electrocatalytic activity of the nanocomposite for p-nitrophenol reduction and methanol oxidation was tested by micro-powderelectrode. The results imply that the electrocatalytic activity of the composite forp-nitrophenol reduction is higher than that of CNT and tungsten carbide withmesoporosity. And the electrocatalytic activity for methanol oxidation of the sampleis higher than that of granular tungsten carbide, tungsten oxide and carbon nanotubepurified. The improvement of the electrocatalytic activity of the sample can beattributed to its components and composite structure. Base on the experimental results,the mechanism of the electro-reaction was proposed.Based on the above results, one conclusion can be drawn that tungsten carbidedecorating on the outside surface of carbon nanotube is one of the efficacious ways toimprove its electrocatalytic activity.
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