金红石二氧化钛纳米片的性质及其光催化活性

doi:10.15541/jim20150110

摘要/Abstract

摘要：

采用溶胶-凝胶、质子交换和层状剥离的方法, 制备出金红石TiO₂纳米片。利用X射线电子衍射谱(XRD)、透射电子显微镜(TEM)、紫外-可见吸收光谱(UV-Vis)、X光电子能谱(XPS)的价带谱和荧光光谱(PL)等对样品进行了表征, 研究了光生载流子的转移过程。结果证明: 金红石TiO₂纳米片具有较大的比表面积(185.7 m²/g), 厚度约5 nm, 与金红石TiO₂样品相比, 金红石TiO₂纳米片的禁带宽度增加, 氧化还原能力增强; 此外, 纳米片结构能够促使光生载流子快速转移到纳米片的表面并产生有效分离, 阻止了光生电子和空穴的复合, 提高了光催化反应中光生载流子的利用率。金红石纳米片的这些特性导致其具有较高的光催化活性, 紫外光催化降解对氯苯酚的实验表明: 金红石TiO₂纳米片的光催化活性高于金红石TiO₂和锐钛矿TiO₂样品。

关键词: 金红石TiO2纳米片, 比表面积, 能带结构, 光生载流子, 光催化活性

Abstract:

Rutile TiO₂ nanosheets were prepared by Sol-Gel method, proton exchange and delamination method. The samples were characterized by X-ray diffraction (XRD), transmission electron microscope (TEM), UV-Vis diffuse reflectance spectroscope, X-ray photoelectron spectroscope (XPS) and photoluminescence (PL). The transference of photogenerated charge carriers was studied. It is revealed that the rutile TiO₂ nanosheets (thickness 5 nm) exhibit increased specific surface area (185.7 m²/g) and enlarged energy band gap, resulting in enhanced redox ability, when compared with rutile TiO₂ samples. In addition, the photogenerated charge carriers are able to transfer to the surface of nanosheets, due to their unique structure enabling photogenerated charge carriers to be effective separation during photocatalytic reactions. Therefore, the rutile TiO₂ nanosheets can enhance photocatalytic activity. Forthermore, the rutile TiO₂ nanosheets exhibite higher photocatalytic activity than rutile and anatase TiO₂ samples on the photocatalytic degradation of 4-chlorophenol under ultraviolet irradiation.

Key words: rutile TiO2 nanosheet, specific surface area, energy band structure, photogenerated carrier, photo- catalytic activity

中图分类号:

O643
O644

赵丹丹, 于彦龙, 高东子, 曹亚安. 金红石二氧化钛纳米片的性质及其光催化活性[J]. 无机材料学报, 2016, 31(1): 1-6.

ZHAO Dan-Dan, YU Yan-Long, GAO Dong-Zi, CAO Ya-An. Properties and Photocatalytic Activity of Rutile TiO₂ Nanosheets[J]. Journal of Inorganic Materials, 2016, 31(1): 1-6.

图/表 8

图1 r-TiO2 sheet(a)、r-TiO2(b)和a-TiO2(c)样品的XRD图谱

Fig. 1 XRD patterns of r-TiO2 sheet (a), r-TiO2 (b) and a-TiO2 (c) samples

表1 r-TiO2 sheet、r-TiO2和a-TiO2的晶胞参数、晶胞体积和比表面积

Table 1 Cell parameters, cell volume and specific surface area of r-TiO2 sheet, r-TiO2 and a-TiO2 samples

Sample	Cell parameters /nm		Cell volume /nm³	S_BET/(m²·g^-1)
Sample	a=b	c	Cell volume /nm³	S_BET/(m²·g^-1)
r-TiO₂sheet	0.45966	0.29585	0.06251	185.7
r-TiO₂ a-TiO₂	0.45908	0.29549	0.06228	2.6
r-TiO₂ a-TiO₂	0.37884	0.95180	0.13660	63.8

图2 r-TiO2 sheet(a, b)、r-TiO2(c)和a-TiO2(d)样品的TEM (HRTEM)照片

Fig. 2 TEM (HRTEM) images of r-TiO2 sheet (a, b), r-TiO2 (c) and a-TiO2 (d) samples

图3 r-TiO2 sheet(a)、r-TiO2(b)和a-TiO2(c)样品的紫外可见光吸收谱

Fig. 3 UV-Vis diffuse reflectance spectra of r-TiO2 sheet (a), r-TiO2 (b) and a-TiO2 (c) samples

图4 r-TiO2 sheet(a)、r-TiO2(b)和a-TiO2(c)样品的XPS价带谱

Fig. 4 XPS valence band spectra of r-TiO2 sheet (a)、r-TiO2 (b) and a-TiO2 (c) samples

图5 r-TiO2 sheet(a)、r-TiO2(b)和a-TiO2(c)样品的荧光发射谱

Fig. 5 Photoluminescence emission spectra of r-TiO2 sheet (a)、r-TiO2 (b) and a-TiO2 (c) samples

表2 r-TiO2sheet、r-TiO2和a-TiO2样品紫外光催化活性

Table 2 Photocatalytic activity of r-TiO2 sheet, r-TiO2 and a-TiO2 samples under ultra-violet light irradiation

Sample	Degradation ratio^a (Δc/c₀)	K^b/(×10^-3, min^-1)	t_1/2/min	Specific photocatalytic acitivity^c/ (×10^-6, mol·g^-1·h^-1)
Blank^d	0.132	1.80	377	21.78
r-TiO₂	0.469	5.19	128.0	101.6
a-TiO₂	0.776	12.54	60.0	224.0
r-TiO₂sheet	0.979	33.62	22.6	290.5

图6 r-TiO2 sheet(a)、r-TiO2(b)和a-TiO2(c)样品光催化降解对氯苯酚的c~t曲线

Fig. 6 The c-t curves of photocatalytic degradation of 4-chlorophenol by r-TiO2 sheet (a), r-TiO2 (b) and a-TiO2 (c) samples

参考文献 23

[1]	SEO J W, CHUNG H, KIM M Y, et al.Development of water-soluble single crystalline TiO2 anoparticles for photocatalytic cancer-cell treatment.Small, 2007, 3(5): 850-853.
[2]	ADACHI M, MURATA Y, HARADA M, et al.Formation of titania nanotubes with high photo-catalytic activity.Chem. Lett., 2000, 8: 942-943.
[3]	ZHANG H, LI G, AN L, et al.Electrochemical lithium storage of titanate and titania nanotubes and nanorods.J. Phys. Chem. C, 2007, 111(16): 6143-6148.
[4]	ZHANG QING-HONG, GAO LIAN, GUO JING-KUN.Photocatalytic activity of nanosized TiO2.Journal of Inorganic Materials, 2000, 15(3): 556-560.
[5]	YU JIA-GUO, FAN JIA-JIE, LV KANG-LE.Anatase TiO2 nanosheets with exposed(001) facets: Improved photoelectric conversion efficiency in dyesensitized solar cells.Nanoscale, 2010, 2(10): 2144-2149.
[6]	QUAN XIE, YANG SHAO-GUI, RUAN XIU-LI, et al.Preparation of titania nanotubes and their environmental applications as electrode.Environ. Sci. Technol., 2005, 39(10): 3770-3775.
[7]	ZHANG ZHONG-HAI, YUAN YUAN, SHI GUO-YUE, et al.Photoelectrocatalytic activity of highly ordered TiO2 nanotube arrays electrode for azo dye degradation.Environ. Sci. Technol., 2007, 41(17): 6259-6263.
[8]	MACAK J M, ZLAMAL M, KRYSA J, et al.Self-organized TiO2 nanotube layers as highly efficient photocatalysts.Small, 2007, 3(2): 300-304.
[9]	WU LI-YAN, LIU ZHI-FANG, QIN QING, et al.Ionic liquid-assisted synthesis of anatase TiO2 nanotubes and their UV light photocatalytic activities.Chem. J. Chinese Universities, 2014, 35(5): 934-940.
[10]	ZHANG HAI-MIN, HAN YAN-HE, LIU XIAO-LU, et al.Anatase TiO2 microspheres with exposed mirror-like plane facets for high performance dye-sensitized solar cells(DSSCs).Chem. Commun., 2010, 46(44): 8395-8397.
[11]	HAN XI-GUANG, KUANG QIN, JIN MING-SHANG, et al.Synthesis of titania nanosheets with a high percentage of exposed (001) facets and related photocatalytic properties.J. Am. Chem. Soc., 2009, 131(9): 3152-3153.
[12]	HU CHAO, ZHANG XUAN, LI WENTAO, et al.Large-scale, ultrathin and (001) facet exposed TiO2 nanosheet superstructures and their applications in photocatalysis.J. Mater. Chem. A, 2014, 2(7): 2040-2043.
[13]	YU YAN-LONG, ZHANG PENG, GUO LI-MEI, et al.The design of TiO2 nanostructure (nanoparticle, nanotube and nanosheet) and their photocatalytic activity.J. Phys. Chem. C, 2014, 118(24): 12727-12733.
[14]	CAO YONG-QIANG, HE TAO, CHEN YONG-MEI, et al.Fabrication of rutile TiO2-Sn/anatase TiO2-N heterostructure and its application in visible-light photocatalysis.J. Phys. Chem. C, 2010, 114(8): 3627-3633.
[15]	CAO YA-AN, YANG WEN-SHENG, ZHANG WEI-FENG, et al.Improved photocatalytic activity of Sn4+ doped TiO2 nanoparticulate films prepared by plasma-enhanced chemical vapor deposition.New J. Chem., 2004, 28(2): 218-222.
[16]	KIM D S, HAN S J, KWAK S Y.Synthesis and photocatalytic activity of mesoporous TiO2 with the surface area, crystallite size, and pore size. J. Colloid Interface Sci., 2007, 316(1): 85-91.
[17]	ZHAO DAN-DAN, YU YAN-LONG, LONG HUI-JIN, et al.Improved photocatalytic activity of self-assemble TiO2 nanobelts with Au nanoparticles.Appl. Surf. Sci., 2014, 315: 247-251.
[18]	GAO BI-FEN, MA YING, CAO YA-AN, et al.Great enhancement of photocatalytic activity of nitrogen-doped titania by coupling with tungsten oxide. J. Phys. Chem. B, 2006, 110(29): 14391-14397.
[19]	GHICOV A, MACAK J M, TSUCHIYA H, et al.Ion implantation and annealing for an efficient N-doping of TiO2 nanotubes.Nano Lett., 2006, 6(5): 1080-1082.
[20]	SAKOHARA S, TICKANEN L D, ANDERSON M A.Luminescence properties of thin zinc oxide membranes prepared by the sol-gel technique: change in visible luminescence during firing.J. Phys. Chem., 1992, 96(26): 11086-11091.
[21]	SERPONE N, LAWLESS D, KHAIRUTDINOV R.Size effects on the photophysical properties of colloidal anatase TiO2 particles: size quantization versus direct transitions in this indirect semiconductor.J. Phys. Chem., 1995, 99(45): 16646-16654.
[22]	LI D, HANEDA H, HISHITA S, et al.Visible-light-driven NF-codoped TiO2 photocatalysts. 2. Optical characterization, photocatalysis, and potential application to air purification.Chem. Mater., 2005, 17(10): 2596-2602.
[23]	ABAZOVIC N D, COMOR M I, DRAMICANIN M D, et al.Photoluminescence of anatase and rutile TiO2 particles.J. Phys. Chem. B, 2006, 110(50): 25366-25370.