过渡金属掺杂和碳纳米管(CNT)接枝双重改性TiO_2光催化剂

Preparation of TiO_2 Photocatalyst Dual-modified by Transition Metal Doping and Carbon Nanotube (CNT) Grafting

提出了一种过渡金属掺杂和碳纳米管(CNT)双重改性TiO2的新方法:首先采用溶胶-凝胶法合成掺杂镍和铁的二氧化钛基催化剂,然后采用流化床化学气相沉积方法(FBCVD)在二氧化钛基催化剂表面接枝生长CNT,得到CNT/Fe-Ni/TiO2复合光催化剂.通过X射线衍射、扫描电子显微镜、比表面分析、拉曼光谱、紫外-可见吸收光谱、荧光光谱等方法考察了双重改性复合光催化剂CNT/Fe-Ni/TiO2的结构和性能,通过降解亚甲基蓝溶液评价了双重改性复合光催化剂的活性.结果表明,在TiO2表面接枝的CNT具有较好的石墨化结构,CNT生长过程中小部分TiO2由锐钛矿向金红石晶型转变.过渡金属和CNT双重改性有效地克服了TiO2的比表面积小、量子效率低等缺点,明显提高了TiO2的光催化活性.

A new method for the preparation of TiO2 dual-modified by transition metal doping and carbon nanotube （CNT） grafting was proposed. Fe-NiO/TiO2 was prepared by sol-gel method. Then CNTs were grafted on Fe-NiO/TiO2 by fluidized bed chemical vapor deposition （FBCVD） method. The dual-modified CNT/Fe-Ni/TiO2 composite photocatalyst has been characterized by X-ray diffraction （XRD）, Raman spectra, field emission scanning electron microscopy （FESEM）, transmission electron microscopy （TEM）, UV-Vis absorption spectra and photoluminescence spectra. The photocatalytic activities of prepared samples were investigated by the photodegradation of methylene blue （MB）. The results show that CNT grafted on TiO2 had good graphite structure, and small part of TiO2 was transformed from anatase to rutile during FBCVD process. Double modification of transition metals and CNT can effectively overcome intrinsic defects of TiO2 in small specific surface area and low quantum efficiency. And the photocatalytic activity has been improved significantly.