A strategy to fabricate bismuth ferrite (BiFeO3) nanotubes from electrospun nanofibers and their solar light-driven photocatalytic properties
A strategy to fabricate bismuth ferrite (BiFeO3) nanotubes from electrospun nanofibers and their solar light-driven photocatalytic properties
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DOI：
10.1039/c3ra44085k
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发表时间：
2013-01-01
期刊：
影响因子：
3.9
通讯作者：
Subramanian, Balakumar
中科院分区：
文献类型：
--
作者：
Mohan, Sakar;Subramanian, Balakumar
已经开发出一种利用电纺纳米纤维生产铁酸铋 (BiFeO3/BFO) 纳米管的策略。它涉及使用不同的模式将初纺的 BFO/PVP 复合纤维升温至退火温度，这最终决定了 BFO 的最终形态。因此，我们发现使用逐步和直接升温模式达到退火温度，分别产生了 BFO 纳米纤维和纳米管。根据各自的 XRD 图案，发现 BFO 纳米纤维和纳米管中嵌入的平均微晶尺寸分别约为 15 和 20 nm。此外，这些结果也通过高分辨率透射电子显微镜图像得到证实。场发射扫描电子显微镜图像显示，纳米管和纳米纤维的平均直径约为100 nm，长度从一微米到几微米不等，纳米管的内径约为10 nm。通过紫外-可见光吸收和漫反射光谱法对这些 BFO 纳米管和纳米纤维的光学表征显示，其带隙能量约为 2.38 eV，并且在 300 至 500 nm 之间具有宽广的紫外-可见光吸收带，而 BFO 块状颗粒仅在紫外区域显示出吸收。这一观察结果表明这些 1D BFO 纳米结构具有可见光驱动的光学活性。结果，由于其量子效率，BFO 纳米管和纳米纤维的光催化活性均得到改善。然而，与 BFO 块状颗粒和纳米纤维相比，纳米管表现出相对增强的光催化活性。这可能是由于纳米管的内表面和外表面上可能拥有更多的催化物质，从而降解染料分子。观察结果表明，这些一维 BFO 纳米结构可以成为超高效的太阳能光驱动光催化剂，用于环境友好的应用。
A strategy has been developed to produce bismuth ferrite (BiFeO3/BFO) nanotubes from electrospun nanofibers. It involves ramping the temperature to heat the as-spun BFO/PVP composite fibers to their annealing temperature using different modes, which eventually decides the final morphology of the BFO. Accordingly, we found that using step-by-step and direct ramping modes to reach the annealing temperature, yielded nanofibers and nanotubes of BFO, respectively. From the respective XRD patterns, the average crystallite sizes embedded in the BFO nanofibers and nanotubes were found to be around 15 and 20 nm, respectively. Further, these results were also substantiated through high-resolution transmission electron microscopy images. The field emission scanning electron microscopy images showed that the average diameter of the nanotubes and nanofibers was around 100 nm, while the length varied from one to a few micrometers and the inner diameter of the nanotubes was found to be around 10 nm. The optical characterization of these BFO nanotubes and nanofibers by UV-visible absorption and diffuse reflectance spectrometry showed a band gap energy of around 2.38 eV and a broad UV-visible absorption band between 300 and 500 nm, compared to the BFO bulk particles which showed absorption only in the UV region. This observation promised visible light driven optical activity of these 1D BFO nanostructures. As a result, improved photocatalytic activities were observed in both the BFO nanotubes and nanofibers owing to their quantum efficiency. However, the nanotubes showed a relatively enhanced photocatalytic activity compared to the BFO bulk particles and nanofibers. This could be attributed to the fact that the nanotubes might possess more of the catalytic species on the inner and outer surfaces that degrade the dye molecules. The observed results show that these one-dimensional BFO nanostructures can become super-efficient solar light-driven photocatalysts for environmentally benign applications.