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以钛酸四丁酯Ti(OC4H9)4为Ti O2前驱体,Keggin型铬取代的杂多阴离子PW11Cr为可见光活性组分,采用溶胶-凝胶提拉法在玻片表面制备了PW11Cr/Ti O2纳米膜光催化剂,并用UV-Vis DRS、IR、XRD、SEM和TEM等技术手段对催化剂的光吸收性质、化学组成、晶相和表面结构形貌等进行了表征;讨论了膜中PW11Cr和Ti O2相互作用的方式;以染料模型污染物Rh B的可见光催化降解为探针,评估了PW11Cr/Ti O2光催化剂的可见光催化活性,讨论了光催化反应机理,并与Ti O2的光催化反应机理进行了比较;考察了焙烧温度、PW11Cr剂量和溶液p H值对光催化活性的影响;最后用Rh B的循环降解实验评估了催化剂的光催化稳定性。实验结果表明,PW11Cr/Ti O2光催化剂对可见光有明显吸收,较低焙烧温度(100℃)下得到的膜为无定形结构,而较高焙烧温度(500℃)为纳晶结构;前者的光催化活性较高,在200 W金卤灯照射下降解10μmol/L Rh B,120 min的降解率为95%,4 h的COD去除率为72%;羟基自由基是导致Rh B降解的主要氧活性物质;低的膜处理温度,高的PW11Cr负载量和溶液酸性有利于提高PW11Cr/Ti O2膜的光催化活性;经循环重复使用10次,PW11Cr/Ti O2膜的光催化活性仅有较少损失。
The tetragonal Ti (OC4H9) 4 Ti O2 precursor and the Keggin chromium-substituted heteropolyanion PW11Cr were used as visible light active components. The sol-gel method was used to prepare PW11Cr / Ti O2 Nano-film photocatalyst, and characterized by UV-Vis DRS, IR, XRD, SEM and TEM techniques on the light absorption properties of the catalyst, chemical composition, crystal phase and surface structure morphology were discussed PW11Cr and Ti Visible photocatalytic activity of PW11Cr / Ti O2 photocatalyst was evaluated by visible light photocatalytic degradation of dye RhB. The photocatalytic reaction mechanism was discussed and the photocatalytic reaction mechanism with Ti O2 was discussed The effects of calcination temperature, PW11Cr dosage and solution pH on the photocatalytic activity were investigated. Finally, the photocatalytic stability of the catalyst was evaluated by cyclic degradation of Rh B. The experimental results show that the PW11Cr / Ti O2 photocatalyst has obvious absorption of visible light, the film obtained at lower calcination temperature (100 ℃) is amorphous structure, while the higher calcination temperature (500 ℃) is nanocrystalline structure. The former light The catalytic activity was high. Under the irradiation of 200 W metal halide lamp, the degradation rate of 10 mol / L Rh B was 95% at 120 min and 72% at 4 h. The hydroxyl radical was the main oxygen species that led to the degradation of Rh B The results showed that the PW11Cr / Ti O2 film possessed the lowest photocatalytic activity, and the PW11Cr / Ti O2 film had a lower photocatalytic activity loss.