Bi@Bi4Ti3O12/TiO2等离子体复合纤维的制备及增强可见光催化性能

以电纺TiO₂纳米纤维为基质和反应物、乙二醇为还原剂，采用溶剂热法原位合成了新型Bi@Bi₄Ti₃O₁₂/TiO₂等离子体复合纤维。利用XRD、SEM、高倍透射电子显微镜（HRTEM）、XPS、紫外-可见漫反射光谱（UV-Vis DRS）和光致发光图谱（PL）等分析测试手段研究了Bi@Bi₄Ti₃O₁₂/TiO₂复合纤维的结构和性能。结果表明:当反应温度低于210℃时，Bi@Bi₄Ti₃O₁₂/TiO₂复合纤维的Bi₄Ti₃O₁₂纳米片随反应温度升高逐渐缩小、增厚，且有金属Bi纳米粒子生成；当反应温度高于210℃时，Bi@Bi₄Ti₃O₁₂/TiO₂复合纤维的纳米片发生堆积、变形、表面金属Bi被氧化成Bi₂O₃。反应温度对Bi@Bi₄Ti₃O₁₂/TiO₂等离子体复合纤维的形貌和物相组成有重要影响；Bi@Bi₄Ti₃O₁₂/TiO₂复合纤维对罗丹明B表现出优异的光催化活性，可见光照5 h其降解率达97.8%。Bi@Bi₄Ti₃O₁₂/TiO₂复合纤维光催化性能提高归结于Bi₄Ti₃O₁₂与TiO₂间形成异质结、金属Bi等离子体共振效应及等离子体共振效应与异质结的协同作用。 

Preparation and highly enhanced visible-light photocatalytic performances of Bi@Bi4Ti3O12/TiO2 plasmonic composite fibers

A novel Bi@Bi₄Ti₃O₁₂/TiO₂ plasmonic composite fibers was synthesized in situ by solvothermal method using electrospun titanium dioxide nanofibers as matrix and reactant, and ethylene glycol as reductant. The XRD, SEM, high power transmission electron microscope (HRTEM), XPS, UV-visible diffuse-reflectance spectrum and photoluminescence (PL) spectra were employed to explore the structural and properties of Bi@Bi₄Ti₃O₁₂/TiO₂ composite fiber. The results indicate that when the reaction temperature is lower than 210℃, the Bi₄Ti₃O₁₂ nanosheets on the surface of Bi@Bi₄Ti₃O₁₂/TiO₂ composite fiber become smaller and thicker gradually with the increasing reaction temperature, and a large number of metal Bi nanoparticles are evenly formed. When the reaction temperature is higher than 210℃, not only the nanosheets accumulate and deform, but also the metal Bi on the surface is oxidized to Bi₂O₃. The Bi@Bi₄Ti₃O₁₂/TiO₂ composite fiber showed excellent photocatalytic efficiency for the degradation of Rhodamine B, with a Rhodamine B degradation rate of 97.8% after visible light irradiation for 5 h. Adjusting reaction temperature not only exerts a pivotal effect on the morphological structure and phase composition, but also affects the photocatalytic capability of the Bi@Bi₄Ti₃O₁₂/TiO₂ plasmonic composite fibers. The improvement of visible-light photocatalytic performance of Bi@Bi₄Ti₃O₁₂/TiO₂ composite fiber is mainly attributed to the formation of high-quality heterojunctions between Bi₄Ti₃O₁₂ and TiO₂, the plasma resonance effect of metal Bi, and the synergistic effect of plasma resonance effect and heterojunction.