NCDs/TiO2复合材料的制备及其在太阳光下催化制氢的应用

doi:10.15541/jim20150087

无机材料学报 ›› 2015, Vol. 30 ›› Issue (9): 925-930.DOI: 10.15541/jim20150087

NCDs/TiO₂复合材料的制备及其在太阳光下催化制氢的应用

魏婕¹, 李雪冬¹, 王宏志¹, 张青红², 李耀刚¹

(东华大学1. 材料科学与工程学院, 纤维材料改性国家重点实验室; 2. 先进玻璃制造技术教育部工程研究中心, 上海201620)

收稿日期:2015-02-09 修回日期:2015-05-18 出版日期:2015-09-20 网络出版日期:2015-08-19
作者简介:魏婕(1981–), 女, 博士研究生. E-mail: donghuaweijie@163.com
基金资助:
国家自然科学基金(51172042);高等学校学科创新引智计划资助(111-2-04);高等学校博士学科点专项科研基金(20110075130001);教育部创新团队发展计划(IRT1221);上海市科委项目(12nm0503900, 13JC1400200);中央高校基本科研业务费

Nitrogen Doped Carbon Quantum Dots/Titanium Dioxide Composites for Hydrogen Evolution under Sunlight

WEI Jie¹, LI Xue-Dong¹, WANG Hong-Zhi¹, ZHANG Qing-Hong², LI Yao-Gang¹

(1. State Key Laboratory of Modification of Chemical Fibers and Polymer Materials, College of Materials Science and Engineering, Donghua University, Shanghai 201620, China 2. Engineering Research Center of Advanced Glasses Manufacturing Technology, College of Material Science and Engineering, Donghua University, Shanghai 201620, China)

Received:2015-02-09 Revised:2015-05-18 Published:2015-09-20 Online:2015-08-19
About author:WEI Jie. E-mail: donghuaweijie@163.com
Supported by:
National Natural Science Foundation of China(51172042);Program of Introducing Talents of Discipline to Universities(111-2-04);Specialized Research Fund for the Doctoral Program of Higher Education(20110075130001);Innovative Research Team in University(IRT1221);Science and Technology Commission of Shanghai Municipality(12nm0503900, 13JC1400200);Shanghai Natural Science Foundation

摘要/Abstract

摘要：

采用溶剂热法, 以乙腈为溶剂和葡萄糖为原料制备了粒径约4 nm的氮掺杂碳量子点NCDs。当激发波长从330 nm增加到470 nm, NCDs水溶液发射光谱出现红移。随后, 将一定配比的NCDs、TiO₂及5 mL超纯水超声混合60 min, 并在80℃烘箱内陈化24 h, NCDs纳米颗粒成功地复合到TiO₂(TiO₂)表面。该方法有效地拓宽了TiO₂吸收光谱的范围, 并且减少了光生电子和空穴对, 从而增强了TiO₂的光催化制氢性能。实验结果表明: 投料比为m(NCDs):m(TiO₂)=15:85时, 以甲醇为牺牲剂的反应体系光催化制氢效果最好, 该复合材料具有一定的稳定性, 循环三次使用后仍然有一定的光催化制氢性能。

关键词: NCDs, 碳量子点/TiO2复合材料, 太阳光催化制氢, 溶剂热合成

Abstract:

Using acetonitrile as the solvent and glucose as the raw material, nitrogen doped carbon quantum dots (NCDs) were prepared by the solvothermal method. The size of NCDs is around 4 nm. The emission spectrum of NCDs showed red shift when the excitation wavelength of quantum dots increased from 330 nm to 470 nm. Titanium dioxide was coated by NCDs by mixing a certain proportion of NCDs, TiO₂ and ultrapure water through 60 min ultrasonic and aging under 80℃ for 24 h. NCDs/titanium dioxide composites show good photocatalyst performance as compared with pure NCDs and pure titanium dioxide, because the NCDs can expand the absorption spectrum and reduce the photogenerated electrons and holes. The NCDs/TiO₂ composites at the raw ratio of m(NCDs):m(TiO₂)=15:85 show the best hydrogen evolution performance, using methanol as the sacrificial agent. The composite material displays good stability and certain photocatalytic performance after three cycles.

Key words: nitrogen doped carbon quantum dots, nitrogen doped carbon quantum dots/titanium dioxide composite, hydrogen evolution under sunlight, solvothermal reaction

中图分类号:

TQ127

魏婕, 李雪冬, 王宏志, 张青红, 李耀刚. NCDs/TiO₂复合材料的制备及其在太阳光下催化制氢的应用[J]. 无机材料学报, 2015, 30(9): 925-930.

WEI Jie, LI Xue-Dong, WANG Hong-Zhi, ZHANG Qing-Hong, LI Yao-Gang. Nitrogen Doped Carbon Quantum Dots/Titanium Dioxide Composites for Hydrogen Evolution under Sunlight[J]. Journal of Inorganic Materials, 2015, 30(9): 925-930.

图/表 15

图1 为NCDs的透射电镜照片, 由图可以看出, 在乙腈溶剂中加入葡萄糖, 通过溶剂热法制备得到的NCDs尺寸分布均匀, 粒径在4 nm左右。从图1中还可以看出, 通过此方法制备的产物没有明显的团聚现象, 这可能是由于NCDs表面含有亲水性基团, 使其能够稳定分散在水溶液中。

图1 NCDs的TEM照片

Fig. 1 TEM image of nitrogen doped carbon quantum dots

图 2 为NCDs的荧光激发和发射光谱图, NCDs的激发光谱显示, 400 nm左右的激发光可以激发出

图2 NCDs的荧光激发和发射光谱图

Fig. 2 Fluorescence emission and excitation spectra of nitrogen doped carbon quantum dots

图 3 为NCDs的紫外吸收光谱, 插图分别为在日光灯下的NCDs的水溶液和365 nm紫外光激发下显示出蓝色荧光的NCDs的水溶液。从图3可以看出, NCDs从200 nm到800 nm均有吸收, 包括了可见光部分和紫外光部分, 这有利于更好地利用太阳光进行光催化制氢。紫外吸收光谱在280 nm左右非常强的吸收是典型的芳香族π体系吸收[8]。

图 3 NCDs的紫外吸收光谱

Fig. 3 Ultraviolet absorption spectrum of NCDs Inset shows the NCDs solution under daylight lamp and 365 nm excitation

图 4 为NCDs的红外光谱图, 在1051 cm-1的波峰为环氧官能团的伸缩震动; 1633 cm-1的波峰为苯环的C=C键的震动, 正好对应紫外吸收光谱, 证明有大π键存在。1138 cm-1的波峰是C-N键引起的, 由于葡萄糖本身不含有氮元素, C-N键的存在证明乙腈参与了化学反应。3423 cm-1的波峰对应于O-H的伸缩震动, 氮掺杂石墨烯量子点具有良好的亲水性正是O-H所赋予的。1402 cm-1的波峰对应O-H的变形震动[9-10]。

图 4 NCDs的红外光谱图

Fig. 4 Infrared spectrum of NCDs

图 5 NCDs的X射线光电子能谱

Fig. 5 XPS spectra of NCDs((a) Full scan spectrum, (b) C1s and (c) N1s)

图6 NCDs/TiO2复合材料的高分辨透射电镜照片

Fig. 6 HRTEM image of NCDs/TiO2 composite

图 7 NCDs/TiO2复合材料的扫描电镜照片

Fig. 7 SEM image of NCDs/TiO2 composite

图8 NCDs/TiO2复合材料和纯的TiO2的紫外-可见吸收光谱图

Fig. 8 UV-visible absorption spectra of NCDs/TiO2 composite and pure TiO2

图9 NCDs/TiO2复合材料在室温下的荧光光谱, 激发波长为365 nm

Fig. 9 Room temperature photoluminescence spectra of NCDs/TiO2 composite excited by the light with wavelength of 365 nm

图10 投料比为m(NCDs): m(TiO2)=15: 85的条件下制备的复合材料产生氢气的稳定性研究

Fig. 10 Stability study of photocatalytic time course of hydrogen production for the composites prepared at weight ratio of m(NCDs): m(TiO2)=15: 85 The black line indicates using photocatalysis to produce hydrogen for the first time. The red line indicates the second time, and the blue line indicates the third time

图11 纯的NCDs, NCDs/TiO2复合材料和纯的TiO2在太阳光下光催化制氢活性

Fig. 11 Comparison of the photocatalytic hydrogen production activities of pure NCDs, pure TiO2 and NCDs/ TiO2 compound under sunlight

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NCDs/TiO₂复合材料的制备及其在太阳光下催化制氢的应用

Nitrogen Doped Carbon Quantum Dots/Titanium Dioxide Composites for Hydrogen Evolution under Sunlight

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