摘要
为使TiO2能够在可见光下发挥其于紫外激发下的高光催化活性,且易于从处理废水中分离,采用溶胶-凝胶法将TiO2与掺杂稀土离子Er3+的上转换发光剂Er3+:YAlO3结合,再将其负载到球形活性炭(SAC)表面,制备出可见光响应的负载型Er3+:YAlO3/TiO2-SAC光催化剂。通过XRD、EDS、SEM与FSA等手段对制备的光催化剂进行晶相、表面结构与元素分布、发光光谱等表征。以甲基橙为目标污染物,研究制备的光催化剂在可见光下的催化活性。结果表明,Er3+:YAlO3可以作为上转换发光材料,它吸收可见光并发射紫外光进而激发TiO2。700°C煅烧制备的催化剂具有最佳的光催化活性,可见光下表观反应速率常数可达0.0197min-1。
In order to develop the high photocatalytic activity of TiO2 under visible light as that under ultraviolet light and make it easy to be separated from treated liquor, a visible light response and spherical activated carbon (SAC) supported photocatalyst doped with upconversion luminescence agent Er3+:YAlO3 was prepared by immobilizing Er3+:YAlO3/TiO2, which was obtained by combination of Er3+:YAlO3 and TiO2 using sol-gel method, on the surface of SAC. The crystal phase composition, surface structure and element distribution, and light absorption of the new photocatalysts were examined by X-ray diffraction (XRD), energy dispersive X-ray spectra (EDS) analysis, scanning electron microscopy (SEM) and fluorescence spectra analysis (FSA). The photocatalytic oxidation activity of the photocatalysts was also evaluated by the photodegradation of methyl orange (MO) in aqueous solution under visible light irradiation from a LED lamp (λ400 nm). The results showed that Er3+:YAlO3 could perform as the upconversion luminescence agent which converts the visible light up to ultraviolet light. The Er3+:YAlO3/TiO2 calcinated at 700 °C revealed the highest photocatalytic activity. The apparent reaction rate constant could reach 0.0197 min-1 under visible light irradiation.
基金
Projects (50908096, 50908097) supported by the National Natural Science Foundation of China
Project (20100471251) supported by China Postdoctoral Science Foundation
关键词
可见光
上转换发光材料
TIO2
活性炭
光催化
visible light
upconversion luminescence
TiO2
activated carbon
photocatalysis