催化学报 ›› 2017, Vol. 38 ›› Issue (2): 287-295.DOI: 10.1016/S1872-2067(16)62582-2

• 论文 • 上一篇    下一篇

具有高电催化活性的g-C3N4-ZnS-DNA纳米复合材料的制备及应用

周鑫, 邹菁, 张胜, 潘敏, 龚晚芸   

  1. 武汉工程大学化学与环境工程学院, 绿色化学过程教育部重点实验室, 湖北武汉 430205
  • 收稿日期:2016-09-29 修回日期:2016-10-24 出版日期:2017-02-18 发布日期:2017-03-14
  • 通讯作者: Jing Zou,Tel/Fax:+86-27-81624593;E-mail:jingzou@wit.edu.cn
  • 基金资助:

    国家自然科学基金(21471122),武汉工程大学研究生教育创新基金及校长基金(CX2015147,2016062).

Preparation and application of g-C3N4-ZnS-DNA nanocomposite with enhanced electrocatalytic activity

Xin Zhou, Jing Zou, Sheng Zhang, Ming Pan, Wanyun Gong   

  1. School of Chemistry and Environmental Engineering, Key Laboratory for Green Chemical Process of Ministry of Education, Wuhan Institute of Technology, Wuhan 430205, Hubei, China
  • Received:2016-09-29 Revised:2016-10-24 Online:2017-02-18 Published:2017-03-14
  • Contact: 10.1016/S1872-2067(16)62582-2
  • Supported by:

    This work was supported by the National Natural Science Foundation of China (21471122) and Graduate Student Education Innovation Fundation and President Foundation of Wuhan Institute of Technology (CX2015147, 2016062).

摘要:

g-C3N4作为丰富的可见光光催化剂,具有独特的二维结构,优异的化学稳定性和可调的电子结构;但因其激子结合能高和结晶度较低,导致其光催化过程量子效率偏低,限制了光催化剂的推广应用.根据g-C3N4独特的可调电子结构,将其与半导体材料进行耦合,形成异质结构,通过调控半导体的能带结构,优化其光吸收能力,促进光生电子-空穴对的快速分离,从而抑制光生载流子的复合,提高其光催化效率.目前,人们已发展了许多g-C3N4与窄禁带和宽禁带半导体耦合形成的二元纳米复合材料,广泛应用于光催化降解污染物、光催化水解产氢和光催化还原将温室气体CO2转换成有用的碳氢燃料等方面,但关于g-C3N4基的三元复合光催化剂,尤其与天然纳米材料DNA复合,研究其电催化性能的却鲜有报道.近年来,随着环境污染日益严重,被称为环境激素的五氯酚(PCP)、壬基酚(NP)等一系列环境激素在水体和土壤等环境介质中长期残留,难以降解,且容易聚集在生物体内,通过空气循环和食物链等方式进入人体,对环境和人体产生极大的危害,所以越来越多的人致力于环境激素的高效筛选和检测的研究.常规的分析方法已经很难满足人们对环境激素的高灵敏检测的要求,而电化学方法因其操作简单、成本低廉、选择性好、灵敏度高、样品前处理简单等特点而备受关注.
本文成功设计和制备了g-C3N4-ZnS-DNA三元纳米复合材料.首先,采用水热法制备了ZnS半导体纳米片,采用热解法制备了g-C3N4纳米片,接着将它们与DNA复合,成功制备了g-C3N4-ZnS-DNA纳米复合材料,通过苯胺聚合法修饰到玻碳电极表面,成功构建了NP和PCP环境激素新型的电化学传感器.通过透射电镜、X射线衍射、紫外-可见漫反射光谱和X射线光电子能谱等对其形貌、结构及组分进行了表征.采用CHI660C仪器对新型的电化学传感器的电催化性能进行了系统研究.通过循环伏安法(CV)和示差脉冲伏安法(DPV)研究了NP和PCP在g-C3N4-ZnS-DNA-GCE修饰电极的上的电化学行为.
电化学阻抗谱表明,g-C3N4-ZnS-DNA纳米复合材料大大促进了修饰电极的电子传递能力,与g-C3N4膜相比,ZnS和DNA共掺杂的g-C3N4膜对NP和PCP的电化学响应明显提高,峰电流是g-C3N4膜的2倍,电催化活性明显增强.在最优化条件下,NP和PCP检测的线性范围分别为2.0×10-5-1.0×10-8和1.0×10-5-1.0×10-8 mol L-1,检出限均为3.3×10-9 mol L-1.将g-C3N4-ZnS-DNA-GCE修饰电极用于湖水中NP和PCP的测定,其回收率均高于90%,证明g-C3N4-ZnS-DNA纳米复合材料修饰电极可应用实际水样中痕量环境激素的测定.同时,我们分析了电催化活性增强的原因:(1)DNA分子通过C-O-C键连接到g-C3N4表面,导致ZnS纳米片组装成线性超结构,形成稳定的g-C3N4-ZnS-DNA纳米复合材料;(2)由于DNA和PCP或NP之间的相互作用使得电极表面上的PCP和NP的浓度增加;(3)纳米复合材料聚苯胺膜可促进电子转移和加速PCP或NP向电极表面的扩散;并提出了Z型g-C3N4-ZnS-DNA纳米复合材料的电子转移路径,以及PCP和NP的可能的电催化氧化机理.

关键词: 氮化碳, 硫化锌, DNA, 纳米复合材料, 电催化活性, 环境激素

Abstract:

We successfully designed and prepared a g-C3N4-ZnS-DNA nanocomposite by a simple method and systematically investigated its morphology, microstructure, and electrocatalytic properties. The as-prepared g-C3N4-ZnS-DNA nanocomposite possessed the electrocatalytic activity of g-C3N4-ZnS and the conductivity of DNA. The presence of DNA was found to enhance the electrocatalytic response of the nanocomposite towards environmental hormones, e.g. pentachlorophenol and nonylphenol, owing to the interaction between g-C3N4-ZnS and DNA, indicating that a stable nanocomposite was formed. The three components showed synergistic effects during electrocatalysis. Electrochemical impedance spectra indicated that the g-C3N4-ZnS-DNA nanocomposite dramatically facilitated the electron transfer of a modified electrode. The co-doping of g-C3N4 film with ZnS and DNA doubled the electrochemical response of the modified electrode in comparison with that of unmodified g-C3N4 film. The detection limits (3 S/N) of pentachlorophenol and nonylphenol were 3.3×10-9 mol L-1. Meanwhile, we propose a possible Z-scheme mechanism for electron transfer in the g-C3N4-ZnS-DNA nanocomposite and the possible pentachlorophenol and nonylphenol electrocatalytic oxidation mechanism. The g-C3N4-ZnS-DNA nanocomposite-modified electrode was demonstrated to be effective for electrochemical sensing of trace environmental hormones in water samples.

Key words: Graphitic carbon nitride, Zinc sulfide, DNA, Nanocomposite, Electrocatalytic activity, Environmental hormones