Preparation, Characterization And Catalytic Oxidation Property Of SiO₂/RuO₂/CNTs Nanohybrids

Nanohybrids have been receiving considerable attention owing to their unique structure and extraordinarily properties. Among all the hotspots rising from them, silica nanohybrids was one of the most important research field. The research and development of these silica nanohybrids for new catalytic materials to improve the limitations and shortages of the traditional catalytic materials is of great theoretic significance for the development of nanoscience and catalysis research.In this thesis, we managed to improve the catalytic activity and selectivity of RuO2/CNTs nanocatalyst by means of coating SiO2 layer. To prepare the carbon nanotube (CNT) supported SiO2 nanocatalyst, TEOS was hydrated nonaqueously over CNTs pre-adsorbing APTES at 5 oC. The thickness of SiO2 layer was uniform and controllable. Some factors influencing the layer thickness, particularly adsorbent and reaction temperature, were discussed in details. This method was used to prepare the SiO2/RuO2/CNTs catalyst. The porous SiO2 layer effectively inhibits the sintering of RuO2 nanoparticles in the catalyst.The performance of the SiO2/RuO2/CNTs catalyst was studied by two probing reactions, i.e. the competitive oxidation of n-butanol and i-butanol and the oxdiatvie dehydrogenation of methanol at low temperatures. The porous SiO2 layer increased the selectivity of n-butanol in its competitive aerobic oxidation with i-butanol. The SiO2/RuO2/CNTs nanocatalyst exhibited excellent stability and selectivity in the methanol oxidation compared with the RuO2/CNTs nanocatalyst. The structure of the SiO2 layer can be further conditioned via the thermal treatment and chemical etching. The method proposed in this thesis provided a potential application of SiO2 nanohybrids in catalysis.