复合材料BiOI/BiOCl的制备及可见光催化降解活性艳红X-3B

以乙二醇为溶剂,利用溶剂热方法制备了不同I/Cl比的BiOI/BiOCl可见光催化材料.同时,采用X射线衍射光谱(XRD)、X射线光电子能谱(XPS)、紫外可见漫反射光谱(DRS)和光致荧光光谱(PL)对所制备材料的晶相、元素价态和光学性质等进行了表征,并以活性艳红X-3B为目标化合物,研究了不同I/Cl比对X-3B光催化降解动力学的影响.分析结果表明,BiOI和BiOCl能够得到很好的复合,在可见光范围内有很好的吸收.降解实验结果表明,I/Cl摩尔比为9∶1时,复合材料对X-3B的可见光降解效率最高,一级反应动力学速率为0.0133 min-1;TOC和COD在3 h内分别降低28%和25%左右,证明能够对所选目标染料在一定程度上实现矿化;在光催化降解活性艳红X-3B过程中起主要作用的为光生空穴.此外,还对复合材料光催化性能提高机理进行了探索与推测.

Preparation of composite material BiOI/BiOCl and its visible-light photocatalytic degradation of Reactive Red X-3B

Composite materials BiOI/BiOCl with different I/Cl molar ratios were successfully synthesized through an EG-assisted one-pot solvothermal method. Their crystalline phase, valence state of elements and optical property were characterized by X-ray diffraction(XRD),X-ray photoelectron spectroscopy(XPS),UV-Vis diffuse reflectance spectroscopy(UV-DRS) and Photoluminescence(PL). The results showed that composite materials had a good absorption capacity for visible light. Visible light photocatalytic activities of composite materials prepared were evaluated by degrading reactive red X-3B. The results indicated that the visible-light degradation efficiency of reactive red X-3B was the best over BiOI/BiOCl, whose ratio of I/Cl was 9:1, and its first-order kinetic rate constant was 0.0133 min^-1. TOC and COD decreased 28% and 25% in 3 h, respectively, which meant the partial mineralization of reactive red X-3B using the material. The main reactive species in photocatalytic degradation process was photogenerated hole. In addition, the possible mechanism for the improvement of photocatalytic activity was proposed.