摘要
采用低温水热法制备氢钛酸管,通过吸附-煅烧法制备Cu掺杂TiO_2纳米管(Cu-TNT)催化剂.利用X射线衍射(XRD)、电感耦合等离子体-原子发射光谱(ICP-AES)、X射线光电子能谱(XPS)、透射电镜(TEM)、紫外-可见漫反射光谱(UV-Vis-DRS)和电化学测试手段对样品进行表征,并进行平面波赝势密度泛函理论(DFT)计算.结果表明,样品中Cu/Ti原子比接近理论值,Cu掺杂进入TiO_2晶格内部,诱发催化剂可见光活性.掺Cu后,Cu 3d轨道和O 2p轨道杂化形成价带顶,价带负向偏移,样品禁带宽度减小为2.50-2.91 eV,具有可见光响应.以甲苯为模型污染物研究催化剂对挥发性有机化合物(VOCs)的催化去除和矿化效果.未掺杂的TNT可见光催化活性较差;Cu掺杂量超过0.1%(Cu/Ti原子比)时,样品催化活性也减弱;Cu掺杂量为0.1%的催化剂具有最佳可见光催化氧化能力,7 h内甲苯的去除率达77%,甲苯的矿化率达59%.
Based on hydrogen titanate nanotubes prepared by a low-temperature hydrothermal technique, Cu-doped titania nanotube （Cu-TNT） catalysts were prepared using absorption-calcination methods. They were characterized by X-ray diffraction （XRD）, inductively coupled plasma-atomic emission spectroscopy （ICP-AES）, X-ray photoelectron spectroscopy （XPS）, transmission electron microscopy （TEM）, UV-Vis diffuse reflectance spectroscopy （UV-Vis-DRS）, and electrochemical techniques. Density functional theory （DFT） was used to calculate the nanotube band structure and density of states. Cu/Ti atomic ratios in the synthesized powders were very close to the nominal values, and the Cu-doped TiO2 lattice exhibited improved visible-light absorption. This was because the valence band, formed by hybridization of O 2p states with Cu 3d states, was negatively shifted. Thus, the band gap was reduced to 2.50-2.91 eV and the samples exhibited visible-light responses. Toluene was chosen as a model pollutant to evaluate the removal capacity and the CO2 mineralization rate of volatile organic compounds under visible light. Pure TNT displayed poor visible-light activity, and the activities of samples with 〉0.1% Cu doping were also weak. Samples doped with 0.1% Cu exhibited optimum visible-light photocatalytic oxidation activity, with a 77% toluene degradation efficiency and a 59% mineralization rate in7h.
出处
《物理化学学报》
SCIE
CAS
CSCD
北大核心
2013年第10期2232-2238,共7页
Acta Physico-Chimica Sinica
基金
国家自然科学基金(51178412
51278456)
浙江省教育厅科研项目(Z201122663)资助~~
关键词
水热法
吸附-煅烧法
电化学
密度泛函理论
挥发性有机化合物
二氧化碳
Hydrothermal method
Impregnation-calcination method
Electrochemical
Density functional theory
Volatile organic compounds
CO2
