催化学报

催化学报 ›› 2020, Vol. 41 ›› Issue (1): 209-218.DOI: 10.1016/S1872-2067(19)63470-4

• 其他光催化应用 • 上一篇    下一篇

静电纺丝-碱热法制备高活性由纳米片组装的TiO2纳米纤维

陆亚超a, 欧小雨a, 王文广b, 范佳杰c, 吕康乐a   

  1. a 中南民族大学资源与环境学院, 催化转化与能源材料化学教育部重点实验室, 湖北武汉 430074;
    b 广东工业大学材料与能源学院, 广东广州 510006;
    c 郑州大学材料科学与工程学院, 河南郑州 450001
  • 收稿日期:2019-06-23 修回日期:2019-08-09 出版日期:2020-01-18 发布日期:2019-10-22
  • 通讯作者: 吕康乐, 王文广
  • 基金资助:
    国家自然科学基金（51672312和21373275）；中南民族大学中央高校基本科研业务费专项资金（CZT19006）.

Fabrication of TiO2 nanofiber assembly from nanosheets (TiO2-NFs-NSs) by electrospinning-hydrothermal method for improved photoreactivity

Yachao Lua, Xiaoyu Oua, Wenguang Wangb, Jiajie Fanc, Kangle Lva   

  1. a Key Laboratory of Catalysis and Energy Materials Chemistry of Ministry of Education, College of Resources and Environmental Science, South-Central University for Nationalities, Wuhan 430074, Hubei, China;
    b School of Materials and Energy, Guangdong University of Technology, Guangzhou 510006, Guangdong, China;
    c School of Materials Science and Engineering, Zhengzhou University, Zhengzhou 450001, Henan, China
  • Received:2019-06-23 Revised:2019-08-09 Online:2020-01-18 Published:2019-10-22
  • Supported by:
    This work was supported by the National Natural Science Foundation of China (51672312, 21373275) and the Fundamental Research Funds for the Central Universities, South-Central University for Nationalities (CZT19006).

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摘要： 半导体光催化有望解决日益严峻的环境污染与能源危机，因而得到广泛重视.纳米TiO2因为其强的氧化能力和良好的（光）化学稳定性与生物相容性，成为了最受欢迎的半导体光催化材料.到目前为止，材料科学家们制备了多种形貌的TiO2光催化材料，如纳米棒（线）、纳米片和空心微球等.
作为染料太阳能电池的光阳极材料，小颗粒尺寸的纳米TiO2具有大的比表面积，有利于敏化剂的吸附，从而增强太阳能电池的光电转换性能.但是尺寸太小的TiO2颗粒不利于光散射，导致入射的太阳光直接穿透光阳极薄膜而不利于吸收和利用太阳光.为了解决敏化剂吸附和增强光散射这对矛盾，本文设计制备了由纳米片组装的TiO2纳米纤维：（1）首先通过静电纺丝法制备TiO2纳米纤维前躯体；（2）将TiO2纳米纤维前驱体在500℃焙烧，去除有机物，得到晶化度良好的由纳米颗粒组装的TiO2纳米纤维；（3）将TiO2纳米纤维进行NaOH碱热处理，使TiO2纳米颗粒转化成钛酸盐纳米片，然后经历酸洗和焙烧，得到由纳米片组装的TiO2纳米纤维.染料敏化太阳能电池的性能测试结果显示，碱热2.5h所得TiO2样品的光阳极薄膜的光电转化效率提升了2.3倍；同时，利用丙酮光催化分解的活性来评价纳米纤维的光催化活性，发现碱热2.5h所得纳米纤维上光催化降解丙酮的活性提升了3.1倍.
结构表征结果显示，随着碱热时间的延长，从纤维表面生长出来的纳米片逐渐变长，催化剂的比表面积和孔容不断增加.大的比表面积有利于底物的吸附，纳米片结构有利于增强光散射，通过延长光程增强对光的利用效率，从而提升纳米纤维的光活性.光电流测试的结果显示，与碱热前的TiO2纳米纤维相比，碱热后的TiO2纳米纤维光电流显著增强，这是由于纳米片结构减小了扩散距离，有利于光生载流子快速转移到催化剂表面，引发丙酮的光催化氧化.

关键词: TiO2纳米纤维, 静电纺丝, 光催化氧化, 丙酮, 染料敏化太阳能电池

Abstract: Hierarchically structured nanomaterials have attracted much attention owing to their unique properties. In this study, TiO2 nanofibers assembled from nanosheets (TiO2-NFs-NSs) were fabricated through electrospinning technique, which was followed by hydrothermal treatment in NaOH solution. The effect of hydrothermal reaction time (0-3 h) on the structure and properties of TiO2 nanofibers (TiO2-NFs) was systematically studied, and TiO2-NFs was evaluated in terms of the photocatalytic activity toward photocatalytic oxidation of acetone and the photoelectric conversion efficiency of dye-sensitized solar cells. It was found that (1) hydrothermal treatment of TiO2-NFs in NaOH solution followed by acid washing and calcination results in the formation of TiO2-NFs-NSs; (2) upon extending the hydrothermal reaction time from 0 h to 3 h, the BET surface area of TiO2-NFs-NSs (T3.0 sample) increases 3.8 times (from 28 to 106 m2 g-1), while the pore volume increases 6.0 times (from 0.09 to 0.54 cm3 g-1); (3) when compared with those of pristine TiO2-NFs (T0 sample), the photoreactivity of the optimized TiO2-NFs-NSs toward acetone oxidation increases 3.1 times and the photoelectric conversion efficiency increases 2.3 times. The enhanced photoreactivity of TiO2-NFs-NSs is attributed to the enlarged BET surface area and increased pore volume, which facilitate the adsorption of substrate and penetration of gas, and the unique hollow structure of TiO2-NFs-NSs, which facilitates light harvesting through multiple optical reflections between the TiO2 nanosheets.

Key words: TiO2 nanofiber, Electrospinning, Photocatalytic oxidation, Acetone, Dye-sensitized solar cell