催化学报 ›› 2019, Vol. 40 ›› Issue (5): 631-637.DOI: 10.1016/S1872-2067(19)63309-7

• 论文 • 上一篇    下一篇

具有光增强芬顿活性的有序介孔Fe/TiO2的制备

许振民, 郑茹, 陈瑶, 朱建, 卞振锋   

  1. 上海师范大学, 资源化学教育部重点实验室, 稀土功能材料上海市重点实验室, 上海 200234
  • 收稿日期:2018-12-30 修回日期:2019-01-19 出版日期:2019-05-18 发布日期:2019-03-30
  • 通讯作者: 卞振锋
  • 基金资助:

    国家自然科学基金(21876114,21761142011,51572174);上海市曙光学者(17SG44);资源化学国际合作联合实验室(IJLRC);环境功能材料教育部创新团队(PCSIRT_IRT_16R49);上海市东方学者人才计划.

Ordered mesoporous Fe/TiO2 with light enhanced photo-Fenton activity

Zhenmin Xu, Ru Zheng, Yao Chen, Jian Zhu, Zhenfeng Bian   

  1. Key Laboratory of Resource Chemistry, Ministry of Education, Shanghai Key Laboratory of Rare Earth Functional Materials, Shanghai Normal University, Shanghai 200234, China
  • Received:2018-12-30 Revised:2019-01-19 Online:2019-05-18 Published:2019-03-30
  • Contact: S1872-2067(19)63309-7
  • Supported by:

    This work was supported by the National Natural Science Foundation of China (21876114, 21761142011, 51572174), Shanghai Government (17SG44), International Joint Laboratory on Resource Chemistry (IJLRC), and Ministry of Education of China (PCSIRT_IRT_16R49). Research is also supported by The Program for Professor of Special Appointment (Eastern Scholar) at Shanghai Institutions of Higher Learning and Shuguang Research Program of Shanghai Education Committee.

摘要:

Fenton反应能够无选择性地降解有机物,甚至能够处理一些不能被生物降解的污染物,其原理为过氧化氢(H2O2)和亚铁离子(Fe2+)在酸性溶液中生成具有强氧化性的羟基自由基(·OH),后者将有机物氧化分解.因此,Fenton反应在处理环境问题中占有重要地位.将光催化与Fenton反应结合,相比单独的Fenton反应可提高氧化矿化性能,大大加快反应速率,减少H2O2使用量,降低成本,拓宽反应pH范围,其协同作用主要体现在两方面:(1)光催化产生的电子加速Fe3+转变成Fe2+,促进Fenton反应进行;(2) Fenton反应中的H2O2与光生电子反应降低了电子-空穴的复合率,从而提高光催化降解效率.由于协同作用的存在,污染物的降解效率大大增加.
到目前为止,Fenton反应中催化剂的载体多为惰性多孔材料,如沸石、粘土、金属氧化物、介孔二氧化硅、多孔碳和sp2型石墨(石墨烯、氧化石墨烯、碳纳米管等)等具有较大比表面积的材料.通常,增加载体的表面积有利于活性位点的分散,但是大比表面积的载体材料会削弱铁催化剂组分之间的相互作用,导致催化剂稳定性差,循环利用几次后会增加铁浸出量.因此,寻求大比表面积和高稳定性的光催化材料依然是巨大的挑战.
本文首次通过蒸发诱导自组装法成功制备了Fe离子修饰的有序介孔TiO2(FT-X),并通过XRD、BET、TEM、XPS和UV-Vis等分析手段对催化剂的结构进行了表征,同时以光芬顿降解罗丹明B反应考察了pH、污染物浓度及载体(TiO2)结构对催化性能的影响.结果表明,由于Fe离子修饰减小了TiO2的禁带宽度,FT复合材料具有更宽的可见光响应距离和更强的可见光吸收,在光芬顿反应过程中可以迅速转移电子,避免电子-空穴对的重组,同时加速了Fe3+和Fe2+的转化,显著提高了催化剂的催化性能.另外,将Fe离子原位锚定在有序介孔TiO2的孔壁上,使FT具有规整的孔道结构和高的比表面积.与不规则多孔材料相比,一方面,该结构有利于活性位点的暴露,另一方面,有序的孔道更有利于光吸收和溶质传输.同时,Fe离子与载体之间具有较强的相互作用,可以有效地抑制反应过程中Fe离子的流失,FT-1.5样品(Fe:Ti摩尔比为1.5%)在经过5次循环测试后依然保持较高的催化活性.

关键词: 有序介孔TiO2, 铁离子掺杂, 光芬顿, 光催化

Abstract:

Ordered mesoporous Fe/TiO2 was prepared by an evaporation-induced self-assembly method. The iron ions were in situ embedded in the pore wall of the TiO2 framework. The catalyst has excellent light-assisted Fenton catalytic performance under UV and visible light irradiation. X-ray diffraction and transmission electron microscopy results showed that the TiO2 samples have an ordered two-dimensional hexagonal pore structure and an anatase phase structure with high crystallinity. The ordered pore structure of the TiO2 photocatalyst with a large specific surface area is beneficial to mass transfer and light harvesting. Furthermore, iron ions can be controlled by embedding them into the TiO2 framework to prevent iron ion loss and inactivation. After five cycles, the reaction rate of the ordered mesoporous Fe/TiO2 remained unchanged, indicating that the material has stable performance and broad application prospects for the purification of environmental pollutants.

Key words: Ordered mesoporous TiO2, Iron doping, Photo-Fenton, Photocatalysis