原位构筑溴氧化铋/聚吡咯复合材料用于光催化降解阴离子染料

采用光化学反应法在稀酸条件下制备出薄片状溴氧化铋（BiOBr），将其分散于含有过硫酸铵和十六烷基三甲基溴化铵的水溶液中，通过吡咯的一步聚合反应原位制备出聚吡咯（PPy）修饰的BiOBr复合材料（BiOBr/PPy）。通过扫描电子显微镜、透射电子显微镜、X射线衍射、拉曼光谱、X射线光电子能谱、紫外可见光谱及荧光光谱等综合表征技术对样品的晶体结构、形貌特征和光电特性等进行测试。结果显示，PPy成功修饰到BiOBr薄片上，BiOBr与PPy接触紧密且相互作用强。与纯BiOBr相比，BiOBr/PPy复合材料具有更强的可见光吸收效率和增强的光催化降解甲基橙（MO）染料活性。通过优化PPy和BiOBr的组合比例，当BiOBr质量分数约为7%时，BiOBr/PPy-2在50 min内对MO （30 mg·L^-1）的降解率为87.3%；另外，循环光催化活性虽有降低但仍高于纯BiOBr和纯PPy （10.4%）。这表明BiOBr与PPy之间较强的相互作用和良好的界面结合可以有效地促进光生电子与空穴的分离效率。反应体系中分离的光生空穴、衍生自由基在染料氧化降解中发挥了重要作用。

In-Situ Construction of BiOBr/Polypyrrole Composite for Photocatalytic Degradation of Anionic Dyes

Thin bismuth bromide oxide (BiOBr) flake was prepared by photochemical reaction under dilute acid condition, and a new type of bismuth oxide/polypyrrole (BiOBr/PPy) composite was prepared in-situ through a one-step polymerization reaction of pyrrole dispersed in an aqueous solution containing ammonium persulfate and cetyltri-methylammonium bromide. The scanning electron microscope, transmission electron microscope, X-ray diffraction, Raman spectra, X-ray photoelectron spectra, ultraviolet and visible spectra, and fluorescence spectra were used to characterize the crystal structure, morphology feature, and photoelectric characteristics of the samples. The results showed that PPy was successfully modified onto BiOBr flakes with strong interaction and close contact. Compared with pure BiOBr, BiOBr/PPy composite showed superior visible light absorption efficiency and enhanced photocatalytic degradation activity of methyl orange (MO) dye. By optimizing the combination ratio of PPy and BiOBr, the degradation efficiency of MO (30 mg·L^-1) by BiOBr/PPy-2 with a ca. 7% mass fraction of BiOBr was 87.3% in 50 min photoreaction, and the cyclic photocatalytic activity was reduced but still higher than that of pure BiOBr and pure PPy (10.4%). These results indicated that the strong interaction and good interface combination between BiOBr and PPy can effectively promote the separation efficiency of photogenerated electrons and holes. The photogenic holes separated and free radicals derived in this reaction played an important role in oxidative degradation of dye.