物理化学学报 >> 2013, Vol. 29 >> Issue (06): 1327-1335.doi: 10.3866/PKU.WHXB201303212

催化和表面科学 上一篇    下一篇

CNTs表面改性与TiO2-CNTs异质结光催化性能

杨汉培, 张颖超, 傅小飞, 宋双双, 吴俊明   

  1. 河海大学环境学院, 河海大学浅水湖泊综合治理与资源开发教育部重点实验室, 南京 210098
  • 收稿日期:2013-01-25 修回日期:2013-03-20 发布日期:2013-05-17
  • 通讯作者: 杨汉培 E-mail:yanghanpei@hhu.edu.cn
  • 基金资助:

    教育部留学归国人员基金(20071256)资助项目

Surface Modification of CNTs and Improved Photocatalytic Activity of TiO2-CNTs Heterojunction

YANG Han-Pei, ZHANG Ying-Chao, FU Xiao-Fei, SONG Shuang-Shuang, WU Jun-Ming   

  1. Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, College of Environment, Hohai University, Nanjing 210098, P.R.China
  • Received:2013-01-25 Revised:2013-03-20 Published:2013-05-17
  • Supported by:

    The project was supported by the Scientific Research Foundation for the Returned Overseas Chinese Scholars, State Education Ministry of China (20071256).

摘要:

碳纳米管(CNTs)混酸(H2SO4/HNO3, 体积比为3:1)超声辅助纯化及氧化植入活性基团-COOH, 进一步借助其转化为酰氯基团, 分别于CNTs 表面共价嫁接亲水性赖氨酸及亲脂性正十八胺基团, 赋予赖氨酸表面改性CNTs 显著水溶(6.85 mg·mL-1)和十八胺表面改性CNTs 显著醇溶(10.15 mg·mL-1)性能. 运用低温水热法以亲水性CNTs 复合TiO2, 溶胶-凝胶法以亲脂性CNTs 复合TiO2, 观察到复合催化剂光催化性能随CNTs 溶剂分散性能增加而明显提升. 运用傅里叶变换红外(FTIR)、激光拉曼、X射线衍射(XRD)、Brunauer-Emmett-Teller 低温氮气吸附、透射电镜(TEM)及X光电子能谱(XPS)等手段表征, 系统探讨CNTs 的表面改性机制及CNTs 溶解分散性能与复合催化剂的光活性的关联. 认为表面改性CNTs 借助Ti-O-C键合促进其与纳米TiO2的异质结合, 从而充分利用CNTs的大比表面积及电荷传输性能促进催化剂的污染物光催化降解.

关键词: 碳纳米管, 表面修饰, 溶解性能, TiO2, 光催化降解

Abstract:

Carbon nanotubes (CNTs) have been ultrasonically treated with the mixed acid (H2SO4/HNO3, 3:1, volume ratio), embedding the active -COOH groups onto the surface of the CNTs. As a result, the acid-treated CNTs serve as chemical reactors for subsequent grafting of L-lysine or octadecylamine (ODA). It was revealed that L-lysine and ODA covalently bond to the surface of the oxidized CNTs through amidation of carboxylic acid groups (CNTs-COOH) and lysine or ODA via intermediate acyl chlorides (CNTs-COCl). The hydrophilic and lipophilic CNTs have high aquatic and ethanol solubility, and the solubility of the surface modified CNTs in water and ethanol were measured to be as high as 6.85 and 10.15 mg·mL-1, respectively. The surface nature of modified CNTs and the properties of TiO2-CNTs composite photocatalysts, which were prepared through sol-gel or low temperature hydrothermal synthesis, were investigated by Fourier transform infrared (FTIR), laser Raman, X-ray diffraction (XRD), Brunauer-Emmett-Teller N2 adsorption, transmission electron microscopy (TEM), and X-ray photoelectron spectrum (XPS). Improved photocatalytic performance was observed for TiO2 coupled by hydrophilic or lipophilic CNT, which were obtained by low temperature hydrothermal and sol-gel synthesis, respectively, and it was revealed that there is an affinity between the photocatalytic performance of TiO2-CNTs hybrids and the dispersibility of CNTs. It is proposed that the improved photocatalytic activity of CNT-TiO2 compared with pure TiO2 photocatalysts can be mainly attributed to the homogeneous and dense dispersion of TiO2 on the modified CNTs and the intimate contact between TiO2 and CNTs, which results in dense heterojunctions at the interface of TiO2 and CNTs through the Ti-O-C structure.

Key words: Carbon nanotubes, Surface modification, Solubility, TiO2, Photocatalytic degradation

MSC2000: 

  • O643