纳米TiO2/碳化植物纤维复合材料的制备与光催化性能

以碳化植物纤维(CPF)为载体，将纳米TiO₂附着于纤维表面，通过浸渍煅烧法和溶剂热法合成纳米TiO₂/CPF复合光催化剂，并对其光催化性能进行了研究。通过SEM、HRTEM、XRD、EDS分析了纳米TiO₂/CPF复合光催化剂的微观结构和化学组成；以光催化降解亚甲基蓝为模型反应，考察复合材料中不同纤维种类和TiO₂负载量对光催化活性的影响。结果表明，在一定范围内随TiO₂负载量的增加，纳米TiO₂/CPF复合材料光催化性能先增强后减弱。纳米TiO₂/CPF复合材料的光催化性能明显提高是由于在TiO₂和碳纤维界面的良好电荷分离能力。降解染料的活性物种有超氧负离子和羟基自由基，但羟基自由基是主要物种。此外，浸渍煅烧法和溶剂热法生成的纳米TiO₂在纤维表面的存在形式不同，浸渍煅烧法生成纳米TiO₂薄膜，包裹纤维；而溶剂热法生成的TiO₂结晶成纳米颗粒，附着于纤维表面。 

Preparation and photocatalytic properties of nano TiO2/carbonized plant fiber composites

The nano TiO₂/carbonized plant fiber (CPF) composite photocatalysts were synthesized by impregnation-calcination and solvothermal methods, anchored with the nano TiO₂ photocatalyst on the surface of carbon fiber, and the photocatalytic properties of the nano TiO₂/CPF composite photocatalysts were studied by photocatalytic degradation of methylene blue. The microstructure and chemical compositions of the nano TiO₂/CPF composite photocatalysts were characterized by SEM, HRTEM, XRD and EDS, and the effects of fiber and loading of TiO₂ on the photocatalytic activity were studied via degradation of methylene blue. The results show that photocatalytic performance of nano TiO₂/CPF composite photocatalysts enhances first and then decreases with the increase of the loading of TiO₂ in a certain range. The improved photocatalytic activity of nano TiO₂/CPF composite photocatalysts can be attributed to the synergistic effect of CPF and TiO₂, and the excellent separation efficiency of charged carriers at the interface of TiO₂ and CPF. The key active species in the reaction are superoxide anions and hydroxyl radical, and the latter is the main species. TiO₂ formed by the impregnation-calcination and the solvothermal exhibits different forms on the surface of the fiber, corresponding to film enclosed the fiber, and crystalline nanoparticles attached on the surface of the fiber, respectively.