金属氧化物(Fe2O3, CuO,NiO)改性对TiO2纳米管阵列光电催化活性的增强效应

采用阳极氧化法和阴极电沉积法制备了Fe2O3,CuO和NiO纳米粒子改性的高度有序的TiO2纳米管(TiO2-NT)阵列.运用场发射扫描电子显微镜(FE-SEM),透射电子显微镜(TEM),X射线衍射(XRD)和紫外-可见漫反射光谱等手段对Fe2O3/TiO2-NT、CuO/TiO2-NT和NiO/TiO2-NT复合电极进行表征.以苯酚为模拟污染物,考察复合电极的光电性能.结果表明,金属氧化物(Fe2O3,CuO,NiO)纳米粒子成功沉积在TiO2-NTs的管口、内壁和管底.金属氧化物改性复合电极的光电催化活性比未改性的TiO2-NTs提高了2倍以上.Fe2O3/TiO2-NTs在可见光区显示出最高的吸收强度.以Fe2O3/TiO2-NTs为阳极处理苯酚废水,光照120min后苯酚去除率达到96%,而未改性的TiO2-NTs的苯酚去除率只有41%.此外,Fe2O3/TiO2-NTs在生成低毒中间产物方面表现出良好的性能.较高的复合电极光电催化活性主要是由于TiO2纳米管和过渡金属氧化物纳米粒子间构筑的高界面面积异质纳米结构,有效地促进了电子转移,抑制了光生电子-空穴对的复合.

Enhanced Photoeletrocatalytic Activity of TiO2 Nanotube Arrays Modified with Simple Transition Metal Oxides (Fe2O3, CuO, NiO)

Composite electrodes consisting of highly ordered,vertically oriented TiO2 nanotube(TiO2-NT) arrays modified with Fe2O3,CuO,and NiO nanoparticles were successfully fabricated by a simple electrochemical anodization and electrodeposition method.Field emission scanning electron microscopy(FE-SEM),transmission electron microscopy(TEM),X-ray diffraction(XRD),and UV-Vis diffuse reflectance spectroscopy were used to characterize the structure and optical properties of the resulting Fe2O3/TiO2-NT,CuO/TiO2-NT,and NiO/TiO2-NT composite electrodes.The photoelectrochemical(PEC) activities of the composite electrodes were evaluated using phenol as a model pollutant.Results indicated that transition metal oxide nanoparticles were deposited on the mouth,tube wall,and base of the TiO2-NTs.The PEC activity of the composite electrodes was over twice that of an unmodified TiO2-NT electrode.The Fe2O3/TiO2-NT electrode showed the highest absorption intensity in the visible light region.After treatment for 120 min,the phenol removal efficiency using the Fe2O3/TiO2-NT anode could reach 96%,while it was only 41% for the unmodified TiO2-NT anode.Moreover,the Fe2O3/TiO2-NT electrode tended to generate intermediates of low toxicity.The higher PEC activity of the composite electrodes was attributed to the presence of hetero-nanostructures with high interfacial area comprised of TiO2-NTs and transition metal oxide nanoparticles,which efficiently facilitated electron transfer and inhibited the recombination of photogenerated electron-hole pairs.