TiO_2纳米管负载V_2O_5催化剂的制备、表征及其在3-甲基吡啶氨氧化反应中的应用

Preparation and characterization of TiO_2 nanotubes supported V_2O_5 catalysts and their application in the ammoxidation of 3-picoline

采用10 mol/L NaOH溶液对商品化TiO2进行碱处理制备TiO2纳米管,通过X射线粉末衍射、N2吸脱附、扫描电镜等手段表征了碱处理温度和时间对TiO2纳米管结构和形貌的影响.研究发现：120-150℃碱处理生成TiO2纳米管,180℃则为纳米棒;400℃焙烧后纳米管的BET比表面积大于100 m^2/g,而纳米棒的比表面积小于50 m^2/g.以TiO2纳米管为载体,采用浸渍法制备V2O5负载的催化剂,拉曼（Ram an）光谱、程序升温还原（H2-TPR）分析等表明钒氧物种在TiO2纳米管表面呈高度分散状态.3-甲基吡啶氨氧化反应结果表明,以120℃制备的TiO2纳米管为载体负载V2O5催化剂的催化选择性最高.

TiO2 nanotubes were prepared via the commercial TiO2 powder treated with 10 mol/L NaOH aqueous solutions.The effects of temperature and time during the base treatment on the structure and morphology of the resulted TiO2 nanotubes were investigated by the characterizations of the XRD,N2 adsorption-desorption,and SEM techniques.TiO2 nanotubes were formed when the commercial sample was treated at temperatures between 120-150 ℃,while the temperature was increased up to 180 ℃,TiO2 nanorods were formed.The BET surface area of the TiO2 nanotubes calcined at 400 ℃ was larger than 100 m2/g,while that of the nanorods was smaller than 50 m2/g.The as-prepared TiO2 nanotubes were used to prepare V2O5/TiO2 catalysts by wet-impregnation,in which V2O5 species were highly dispersed on the support confirmed by the characterization of the Raman and H2-TPR techniques.These catalysts were applied to the ammoxidation of 3-picoline and the results showed that the catalyst prepared using the TiO2 nanotubes obtained by the base treatment at 120 ℃ as the support represented the best catalytic performance in terms of selectivity.