中文摘要：

以多壁碳纳米管（MWNTs）为载体,在煅烧温度200~900℃、煅烧时间1~7 h、溶胶体系pH值为2~10的工艺条件下,采用溶胶-凝胶法制备复合光催化剂（MWNTs/TiO2）。通过其对甲基橙的光催化降解效果对比,评价各种复合光催化剂催化活性之间的差异,结果表明,随着煅烧温度的升高,复合光催化剂中纳米TiO2的晶型由锐钛型逐渐向金红石型转变,500℃时为2种晶型的混合相;pH值为2的强酸性条件有利于形成金红石晶型,pH值为5的中性及弱酸性条件则有利于形成锐钛型,而pH值为3时为2种晶型的混合相;在煅烧温度500℃、煅烧时间3 h、溶胶凝胶体系pH值为3的最佳制备工艺条件下,复合光催化剂催化活性最高,借助扫描电镜发现其TiO2均匀地包覆在多壁碳纳米管管壁上。

英文摘要：

The composite photocatalysts（MWNTs/TiO2）were prepared by the sol-gel method with multi-walled carbon nanotubes as the carrier,which were calcinated at 200~900℃ with pH=2~10 for 1~7 hours.By comparing the photocatalytic degradation efficiency of methyl orange,this paper evaluated the difference in catalytic activity between various composite photocatalysts.The results showed that,along with temperature ascension,the crystal form of nano-TiO2 in the composite photocatalysts gradually transformed from anatase to rutile,and it became a mixture phase of the two crystal forms at 500℃.The strong acidic condition with pH=2 was suitable for the formation of anatase form,whereas,neutral and weak acidic condition with pH=5 was suitable for the rutile form,and it became a mixture phase of the two crystal forms with pH=3.Under optimal process condition,calcinated at 500℃ with pH=3 for 3 hours,the composite photocatalysts showed the highest activity.Using SEM images,it is found that the wall of the multi-walled carbon nanotubes is coated evenly with TiO2 after such treatment.