液相合成超小TiO2纳米簇及其光催化性质

doi:10.15541/jim20160625

摘要/Abstract

摘要：

稳定原子团簇是高效催化剂在物质结构上的发展方向。研究将正钛酸四丁酯的水解产物在80℃下水中胶溶得到了粒径2 nm左右的超小TiO₂纳米簇。XRD和HRTEM分析结果显示: 这种超小TiO₂纳米簇为锐钛矿型晶体结构; 采用XPS测定其仅含Ti⁴⁺, 无氧空位缺陷; 采用BET测试其比表面积为269.28 m²/g; 通过紫外-可见透射光谱, 计算光学带隙为3.57 eV, 表现出小尺寸化量子效应。这种超小TiO₂纳米簇在235~340 nm波长范围有强吸收带, 使得其在太阳光照射下可将Cr⁶⁺彻底还原成Cr³⁺。在重铬酸钾溶液中紫外光照下Cr⁶⁺的光催化还原实验发现, 超小TiO₂纳米簇对Cr⁶⁺还原效率比普通TiO₂纳米晶提高了4倍以上。

关键词: 原子团簇, 超小纳米簇, 二氧化钛, 光催化, 六价铬

Abstract:

Atomic clusters are of significant interest in catalysis. Ultra-small TiO₂ nanoclusters, a stable Ti-O cluster with diameters of a few nanometers or less, can exhibit fascinating reactive, optical and electronic properties. In this work, ~2 nm TiO₂ ultra-small nanoclusters were obtained by peptizing hydrolysate of tetrabutyl titanate (TPT) at 80℃. HRTEM and XRD were used to characterize microstructure of the ultra-small TiO₂nanoclusters, which was verified to have crystalline phase anatase. XPS demonstrated that the valence state of Ti atom was Ti⁴⁺ and no oxygen vacancy existed. Optical absorption properties were determined by UV-Vis spectroscopy and demonstrated that the ultra-small TiO₂ nanoclusters had extraordinary strong absorption in the light wavelength range from 235 nm to 340 nm. According to the transmission spectrum, the optical band gap was calculated to be 3.56 eV, indicating an appreciable size-base quantum effect. The specific surface area was analyzed to be 269.28 m²/g for Langmuir surface area and 186.90 m²/g for multi-point BET surface area, respectively. Photocatalytic reduction of Cr⁶⁺ to Cr³⁺ in ultra-small TiO₂ aqueous sol was investigated to estimate the photocatalytic activity. It demonstrated that the reduction rate of Cr⁶⁺ to Cr³⁺ by ultra-small TiO₂ nanoclusters was four times faster than that by widely used nano-crystals one. And owing to extraordinary strong ultraviolet absorption of the former, Cr⁶⁺ was completely reduced to Cr³⁺ under sunlight illumination.

Key words: atom cluster, ultra-small, titanium dioxide, photocatalysis, hexavalent chromium

中图分类号:

TQ174

林景诚, 唐笑, 楚婉怡. 液相合成超小TiO₂纳米簇及其光催化性质[J]. 无机材料学报, 2017, 32(8): 863-869.

LIN Jing-Cheng, TANG Xiao, CHU Wan-Yi. Synthesis and Photocatalysis Property of Ultra-small TiO₂ Nanoclusters in Aqueous Media[J]. Journal of Inorganic Materials, 2017, 32(8): 863-869.

图/表 10

图1 Cr6+标准浓度-吸光度曲线

Fig. 1 Standard concentration-absorbance curve of Cr6+

图2 液相合成超小TiO2纳米簇的过程

Fig. 2 Process of synthesizing ultra-small TiO2 nanoclusters(a) Tetrabutyl titanate (TPT) added into water to produce white precipitation hydrolysis products, and then (b) the hydrolysate peptized into transparent sol

图3 锐钛矿TiO2纳米晶(a)、所合成超小TiO2簇(b)和TBT水解产物(c)的XRD图谱

Fig. 3 XRD patterns of (a) anatase nanocrystals, (b) resulting ultra-small nanoclusters and (c) TBT hydrolysates

图4 所合成超小TiO2纳米簇的高分辨透射电镜(HR-TEM)照片(左)以及相应的原位傅立叶变换结果(右)

Fig. 4 HR-TEM images of the ultra-small TiO2 nanoclusters (left) and the corresponding live FFT results (right)

图5 超小TiO2纳米簇的XPS图谱

Fig.5 XPS spectrum of ultra-small TiO2 nanocluster

图6 超小TiO2纳米簇的N2等温吸附曲线及BET比表面积分析结果

Fig. 6 N2 adsorption and desorption isotherm and BET specific surface area analysis results of the ultra-small TiO2 nanocluster

图7 (a) 2 nm左右的超小TiO2纳米簇和(b) 20 nm左右的TiO2纳米晶的紫外-可见吸收光谱图

Fig. 7 UV-Vis absorption spectra of (a) 2 nm sized ultra-small TiO2 nanoclusters and (b) 20 nm sized TiO2 nanocrystals

图8 超小TiO2纳米簇的紫外-可见透射光谱(a)和光学带隙计算结果(b)

Fig.8 (a) UV-Vis transmissiom spectra of the ultra-small TiO2 nanocluster and (b) its absorption onset value of the first allowed transition

图9 相同浓度的超小TiO2纳米簇溶胶(A)和TiO2纳米晶溶胶(B)分别与一定浓度的重铬酸钾溶液混合后在太阳光下放置3 d前后溶液的变化

Fig. 9 (a) Mixtures of K2Cr2O7 solution with the sol of ultra- small TiO2 nanocluster (A) and that of the TiO2 nanocrystal (B) before sunlight irradiating; (b) after sunlight irradiating for 3 d

图10 相同浓度的超小TiO2纳米簇溶胶(A)和TiO2纳米晶溶胶(B)分别与一定浓度的重铬酸钾溶液混合后在紫外光照射下Cr6+浓度随时间的变化

Fig. 10 Change of Cr6+ concentration with irradiating time for the ultra-small TiO2 nanocluster system (A) and TiO2 nanocrystal system (B) under UV irradiation

参考文献 17

[1]	TYO ERIC C, VAJDA S.Catalysis by clusters with precise numbers of atoms.Nature Nanotechnology, 2015, 10(7): 577-588.
[2]	CHIODO L, SALAZAR M, ROMERO A H, et al. Structure, electronic,optical properties of TiO2 atomic clusters: an ab initio study. The Journal of Chemical Physics, 2011, 135(24): 244704-1-9.
[3]	LINDQVIST M J, NILSINGM, PERRSSON P, et al.DFT study of bare and dye-sensitized TiO2 clusters and nanocrystals.International Journal of Quantum Chemistry, 2006, 106(7): 3214-3234.
[4]	SáNCHEZ-DE-ARMAS R, OVIEDO L, MIGUEL J F, et al. Direct vs indirect mechanisms for electron injection in dye-sensitized solar cells.J. Phys. Chem. C, 2011, 115(5): 11293-11301.
[5]	GALYńSKA M, PERSSON P. Emerging polymorphism in nanostructured TiO2: quantum chemical comparison of anatase, rutile, and brookite clusters.International Journal of Quantum Chemistry, 2013, 113(24): 2611-2622.
[6]	WANG L, LIU B, LI H, et al.Long-range ordered carbon clusters: a crystalline material with amorphous building blocks.Science, 2012, 337(2): 825-828.
[7]	PEARMAIN D, PARK S J, ABDELA A.The size-dependent morphology of Pd nanoclusters formed by gas condensation.Nanoscale, 2015, 7(46): 19647-19652.
[8]	JIN R.Atomically precise metal nanoclusters: stable sizes and optical properties.Nanoscale, 2015, 7(5): 1549-1565.
[9]	PRASENJIT M, SONGHAI X, MIHO Y.Stabilized gold clusters: from isolation toward controlled synthesis.Nanoscale, 2012, 4(14): 4027-4037.
[10]	LAN W, LING Z, JINCAI Z.Green synthesis of shape-defined anatase TiO2 nanocrystals wholly exposed with {001} and {100} facets.Chemical Communications, 2012, 48(96): 11736-11738.
[11]	JIANWEI M, BIN L.Anatase TiO2 microspheres with reactive {001} facets for improved photocatalytic activity.RSC Advances, 2012, 3(4): 1222-1226.
[12]	SHIEN G, HONGYAN N, MINGXIA L.The fabrication and the characterization of a TiO2/titanate nanohybrid for efficient hydrogen evolution.RSC Advances, 2015, 5(17):13011-13015.
[13]	XIAOFEI Q, LIXIN C, FANGLIN D.Fabrication of ordered arrays of CNT/TiO2 nanotubes and their photocatalytic properties.RSC Advances, 2015, 5(27): 20976-20980.
[14]	CESANO F, AGOSTINI G, SCARANO D.Nanocrystalline TiO2 micropillar arrays grafted on conductive glass supports: microscopic and spectroscopic studies.Thin Solid Films, 2015, 590(9): 200-206.
[15]	LLANSOLA-PORTOLES M J, BERGKAMP J J, FINKELSTEIN- SHAPIRO D. Controlling surface defects and photophysics in TiO2 nanoparticles.J. Phys. Chem. A, 2014, 118(8): 10631-10638.
[16]	CHEN C, JUANG K, LEE D.Effects of liming on Cr(VI) reduction and Cr phytotoxicity in Cr(VI)-contaminated soils.Soil Science and Plant Nutrition, 2012, 58(11): 135-143.
[17]	YANG J K, LEE S M, FARROKHI M.Photocatalytic removal of Cr(VI) with illuminated TiO2.Desalination and Water Treatment, 2012, 46(4): 375-380.

液相合成超小TiO₂纳米簇及其光催化性质

Synthesis and Photocatalysis Property of Ultra-small TiO₂ Nanoclusters in Aqueous Media

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