TiO_2/硅柱撑蒙脱石复合材料的制备及其光催化性能

利用溶剂化作用,将十二胺和正硅酸四乙酯同时插层进入十六烷基三甲基有机阳离子改性蒙脱石层间,在十二胺的碱性催化作用下,正硅酸四乙酯在蒙脱石层间原位水解得到硅酸及有机物混合插层蒙脱石,将此混合插层化合物在550℃煅烧后得到具有介孔的硅柱撑蒙脱石载体。用此载体负载TiO2在低温下制备得到了TiO2/硅柱撑蒙脱石纳米复合材料,用XRD、TEM和N2低温吸附-脱附等技术对所制备的载体及复合材料进行了表征。以五氯酚钠的光催化降解为探针反应,考察了复合材料的光催化性能。实验结果表明:复合材料的光催化性能较原始钙钠基蒙脱石负载的催化剂光催化性能有较大提高,柱撑蒙脱石和TiO2在光催化反应中存在较大的协同效应。     

TiO2/石墨烯复合材料的制备及其光催化性能

本文以氧化石墨烯和钛酸丁酯为原料,利用水热法一步制备了TiO2/石墨烯复合光催化材料,研究了氧化石墨烯用量、反应温度、反应时间对TiO2/石墨烯复合材料光催化活性的影响。采用XRD,SEM,TEM和氮气吸附-脱附实验(BET)对复合光催化材料的物相、颗粒粒径、形貌及比表面积进行了表征。结果表明,本实验最佳条件是:氧化石墨烯1mg,制备温度为180℃,反应时间为16 h。产物中的TiO2为锐钛矿晶型,其平均粒径约为18 nm。复合材料的比表面积为170m2/g,平均孔径为12.45 nm。在可见光照射(λ>420nm)下以TiO2/石墨烯为光催化剂对有机染料罗丹明B(Rhodamine B,RhB)进行光催化降解,其光催化活性明显高于相同条件下制备的TiO2。     

不同酸催化剂对有机-钛柱撑蒙脱石复合材料光催化活性的影响

以钛酸丁酯为前驱体,分别采用醋酸和盐酸为溶胶-凝胶法制备TiO2溶胶的酸催化剂,将制备的溶胶分别加入经阳离子表面活性剂十六烷基三甲基溴化铵改性的浙江临安和内蒙古膨润土中,制备了有机-钛柱撑膨润土复合光催化剂,并对其进行XRD,SEM,BET表征.实验结果表明:钛阳离子经交换进入了膨润土层间,并以锐钛矿型的晶形存在,而且制备的复合光催化剂具有较好的层状结构,其比表面积均比相应的未经柱撑的膨润土的比表面积大.并且以甲基橙为目标污染物,考察了所制备的有机-钛柱撑膨润土复合光催化剂的吸附性能和光催化活性,发现两种方法所制备的复合光催化剂均具有较好的光催化活性.但是由于在醋酸介质中溶胶的水解速度较慢,可形成稳定均质的凝胶,因而形成的TiO2粒径相对较小,因此对于不同类型的膨润土,以醋酸为酸催化剂制备的复合光催化剂均比用盐酸为酸催化剂制备的复合光催化剂的催化活性好.     

多孔吸附光催化复合材料在含汞废水治理中的应用研究

以凹凸棒土和活性污泥为材料制备多孔载体,采用溶胶-凝胶法制备光催化剂TiO2和多孔吸附光催化复合材料。通过单因素实验,探究降解汞离子(Hg2+)的最优条件,研究TiO2光催化剂降解汞污染物的机制。结果表明:多孔吸附光催化复合材料质量浓度为20g/L,当pH=7.0时,在紫外光源照射10min,Hg2+的还原率达最大,Hg2+的去除率可达71.58%。最后,考察了利用多孔吸附光催化复合材料处理含甲基汞(CH3-Hg+)废水的可行性。     

TiO_2/改性膨润土复合光催化材料的制备及其性能

本文采用无机和有机两种改性方法对钠基膨润土进行改性,在超声辅助下采用溶胶-凝胶法制备了TiO2/改性膨润土复合光催化材料。用X射线衍射(XRD)和红外光谱(IR)等测试技术对复合材料进行了表征,以TNT的吸附和降解为模型反应,考察了膨润土的改性对复合材料的吸附和光催化性能的影响。实验结果表明:无机改性的膨润土层间距减小,而有机改性膨润土的层间距增大;膨润土的改性提高了其对水中有机物的吸附性能,且能有效地抑制复合材料中TiO2晶粒尺寸,提高复合材料的光催化性能。     

镧掺杂TiO2/有机改性膨润土复合光催化材料的制备及性能

本文采用十六烷基三甲基溴化铵对钠基膨润土进行改性,并以有机改性膨润土作为载体,采用超声辅助溶胶-凝胶法制备了镧掺杂TiO2/有机改性膨润土复合光催化材料,采用X射线衍射(XRD)、傅里叶变换红外(FT-IR)光谱和紫外-可见漫反射吸收光谱(DRS)等测试技术对其进行了表征分析,以TNT溶液作为目标物,考察了复合材料的吸附性能和光催化性能。结果表明:膨润土的有机改性抑制了TiO2的晶粒生长,增强了复合材料的吸光性能,提高了复合材料的吸附和光催化性能。     

硫掺杂TiO2的制备及其光催化降解次甲基蓝研究

以TiCl4、(NH4)2SO4为原料,采用溶胶-凝胶法制备了硫掺杂纳米TiO2,利用XRD、TEM、FTIR等对样品进行了表征,并将其用于光催化降解次甲基蓝溶液.结果表明:制备的纳米TiO2为锐钛矿晶型,具有超强酸特征,平均粒径分布为10～30nm,S掺杂对TiO2的晶粒长大有抑制作用,经过硫掺杂的纳米TiO2光催化活性明显优于纯TiO2.     

溶胶-凝胶法制备纳米TiO2及其光催化活性研究

采用正交设计方法,试验研究了4种因素对溶胶-凝胶法制备纳米TiO2光催化活性的影响,确定了各因素所对应的最佳水平,得到了溶胶-凝胶法制备高光催化活性纳米TiO2的最佳工艺条件;且对最佳工艺条件制备的TiO2和商业粉P-25进行了XRD和UV-Vis吸收光谱分析.结果表明,自制的TiO2由纯锐钛矿组成,其平均晶粒尺寸为18.2 nm,比混晶型的P-25 TiO2晶粒尺寸(24.7 nm)要小.自制TiO2粉在330～370nm的紫外光区的吸收增强,在可见光区的吸收也较P-25有所增强.两者都有利于光催化活性的提高,使得光催化降解甲基橙的活性与P-25相当.     

光催化原位氧化聚合法制备聚吡咯/TiO_2复合材料及其可见光催化降解罗丹明B的性能

在无需引发剂的条件下,通过光催化原位氧化聚合法一步合成了聚吡咯/TiO2纳米复合材料(PPy/TiO2)。采用UV-Vis、XRD、XPS和FTIR技术对吡咯在TiO2表面的聚合过程和复合材料的结构进行了表征。以罗丹明B(RhB)的降解反应研究了PPy/TiO2复合材料的光催化性能。研究表明,紫外光(λ=365nm)激发TiO2形成电子-空穴对,空穴迁移至表面与吸附于TiO2表面的吡咯单体作用,迅速形成吡咯阳离子和低聚体,最终形成聚吡咯并包覆在TiO2的表面。光催化结果表明,PPy/TiO2复合材料可加速RhB在可见光和紫外光下的降解速率,所制备的PPy/TiO2复合材料是一种可应用于光电转化和光催化方面的多功能材料。     

MWNTs-TiO2和AC-TiO2复合材料制备及其在染料吸附降解中的应用

采用溶胶-凝胶法,以钛酸四丁酯为原料,分别以多壁碳纳米管和活性炭为载体,并分别在载体表面上负载纳米TiO2颗粒,制备出碳纳米管-TiO2(MWNTs-TiO2)和活性炭-TiO2(AC-TiO2)两种复合材料。采用X射线粉末衍射(XRD)和透射电子显微镜(TEM)对样品进行表征,结果显示,经500℃热处理后,TiO2主要以锐钛矿形式存在,纳米TiO2颗粒均匀的负载于载体的表面。吸附降解的实验结果表明,MWNTs-TiO2和AC-TiO2两种复合材料对活性染料甲基橙吸附降解效果均好于纯纳米TiO2颗粒,而MWNTs-TiO2复合材料的吸附降解效果更好,更适合作为纳米TiO2光催化载体。     

累托石/聚合物纳米复合材料的新进展

累托石是我国湖北省盛产的铝硅酸盐矿物, 其与蒙脱土极为相似, 但又具有它独特的结构特点, 近年来广泛用于聚合物/层状硅酸盐纳米复合材料的制备. 本文介绍了累托石的结构特性、表面修饰和累托石/聚合物纳米复合材料的结构及制备方法, 总结了累托石/壳聚糖基纳米复合材料及其作为抗菌剂、吸附剂、药物控释材料和基因载体等功能化应用方面的最新研究成果, 并提出了累托石/聚合物纳米复合材料未来的研究方向.     

Effect of surface plasmon resonance on the photocatalytic activity of Au/TiO2 under UV/visible illumination

In this study, gold-loaded titanium dioxide was prepared by an impregnation method to investigate the effect of surface plasmon resonance (SPR) on photoactivity. The deposited gold nanoparticles (NPs) absorb visible light because of SPR. The effects of both the gold content and the TiO2 size of Au/TiO2 on SPR and the photocatalytic efficiency were investigated. The morphology, crystal structure, light absorption, emission from the recombination of a photoexcited electron and hole, and the degree of aggregation were investigated using transmission electron microscopy (TEM), X-ray diffraction (XRD), UV-visible-diffuse reflectance spectra (UV-VIS-DRS), photoluminescence (PL) spectroscopy, and turbidimetry, respectively. Photocatalytic activity was evaluated by the decolorization of methyl orange solution over modified titania under UV and UV/GLED (green light emitting diode) illumination. Au/TiO2 NPs exhibited an absorption peak (530-570 nm) because of SPR. The results of our photocatalytic experiments indicated that the UV-inducedly photocatalytic reaction rate was improved by simultaneously using UV and green light illumination; this corresponds to the adsorption region of SPR. Au/TiO2 could use the enhanced electric field amplitude on the surface of the Au particle in the spectral vicinity of its plasmon resonance and thus improve the photoactivity. Experimental results show that the synergistic effect between UV and green light for the improvement of photoactivity increases with increasing the SPR absorption, which in turn is affected by the Au content and TiO2 size.     

CNT/TiO2复合材料的合成、表征及其光催化性能分析

采用多壁碳纳米管(MWCNTs)为原料,分别以异丙醇钛(TIP)、丙氧基钛(TPP)和四丁氧基钛(TNB)为钛源,苯作为溶刺,制备了CNT/TiO2复合材料.利刖N2吸附等温线,扫描电子显微镜(SEM),X-射线衍射(XRD),能量分散性X-射线分析(EDX)以及紫外吸收光谱对所制CNT/TiO2复合材料进行了表征.并在紫外光照射下,通过亚甲蓝(MB,C16H18N3S·Cl·3H2O)水溶液的转,变测试了CNT/TiO2复合材料的光催化性能.研究结果表明:CNT/TiO2复合材料对MB的降解作用不仅有MWCNT的吸附性和TiO2的光催化性,而且还有MWCNT和TiO2之间的电子转移性.     

Preparation and characterization of photoactive composite kaolinite/TiO(2)

Preparation of nanocomposite kaolinite/TiO(2), using hydrolysis of titanyl sulfate in the presence of kaolin was addressed. A variable (kaolin)/(titanyl sulfate) ratio has been used in order to achieve the desired TiO(2) content in prepared nanocomposites. Calcination of the composites at 600 °C led to the transformation of the kaolinite to metakaolinite and to origination of metakaolinite/TiO(2) composites. The prepared samples were investigated using X-ray fluorescence spectroscopy, X-ray powder diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, thermogravimetry and diffuse reflectance spectroscopy in the UV-VIS region. Structural ordering of TiO(2) on the kaolinite particle surface was modeled using empirical force field atomistic simulations in the Material Studio modeling environment. Photodegradation activity of the composites prepared was evaluated by the discoloration of Acid Orange 7 aqueous solution.     

Mechanical and thermal behavior of non-crimp glass fiber reinforced layered clay/epoxy nanocomposites

Mechanical and thermal properties of non-crimp glass fiber reinforced clay/epoxy nanocomposites were investigated. Clay/epoxy nanocomposite systems were prepared to use as the matrix material for composite laminates. X-ray diffraction results obtained from natural and modified clays indicated that intergallery spacing of the layered clay increases with surface treatment. Tensile tests indicated that clay loading has minor effect on the tensile properties. Flexural properties of laminates were improved by clay addition due to the improved interface between glass fibers and epoxy. Differential scanning calorimetry (DSC) results showed that the modified clay particles affected the glass transition temperatures (T_g) of the nanocomposites. Incorporation of surface treated clay particles increased the dynamic mechanical properties of nanocomposite laminates. It was found that the flame resistance of composites was improved significantly by clay addition into the epoxy matrix.     

PT／TiO2复合粒子光催化降解有机污染物的性能

在CHCl3中以FeCl3为氧化剂通过原位化学氧化方法制备了聚噻吩/二氧化钛(PT/TiO2)复合粒子。通过X射线光电子能谱(XPS)和紫外可见漫反射光谱(DRS)分析,分别研究了PT/TiO2复合粒子的结构和光响应特性。结果表明,复合粒子是由PT包裹在TiO2粒子表面而形成的具有核-壳结构的粒子;复合粒子能吸收200 nm~800 nm波长的光。分别以甲基橙和苯酚为目标污染物,研究了PT/TiO2复合粒子光催化降解污染物的性能。结果表明,具有一定含量聚噻吩的复合粒子光催化降解污染物的性能优于TiO2。     

SiO2/TiO2柱撑层状钛酸的制备及表征

采用预膨润技术成功制备了SiO2/TiO2柱撑层状钛酸。将氢型钛酸TiO2(H)于正丙胺溶液中利用离子交换方法得到正丙胺插层的钛酸C-3TiO,C-3TiO在正硅酸乙酯和异丙醇钛的混合溶剂中160℃溶剂热处理2天,得到SiO2/TiO2柱撑层状钛酸。利用X-射线衍射,红外光谱,透射电子显微镜,热重-差热分析等手段对材料进行表征,结果表明制备材料具有层状结构,层间距为1.1nm。     

Transparent nanocomposites of high refractive index based on epoxy resin and TiO2 nanoparticle

A stepwise sol-gel method for the synthesis of stable colloidal TiO2 using hydrolysis and condensation reactions of titanium tetraisopropoxide (TTP) was investigated. The surface modification was carried out using 3-glycidoxypropyltrimethoxysilane (GPTMS). The particle size range of the modified TiO2 observed by TEM was 3-8 nm. The nanocomposites based on an epoxy resin and the modified TiO2 showed strong UV absorption, but maintained high transmittance within the visible region. TEM images of the nanocomposites confirmed the homogenous and fine dispersion of the TiO2 nanoparticles in the epoxy resin. The refractive index of the nanocomposites increased linearly with increasing TiO2 content. With 60% TiO2 by weight, the transmittance and refractive index of the nanocomposite were 98.4% and 1.657, respectively.     

铝硅酸盐中间体对TiO2纳米粒子团聚及相转变的抑制

以粉煤灰为原料, 通过与NaOH煅烧、水解合成铝硅酸盐中间体(ASI), 向sol-gel法制备的TiO₂溶胶中加入ASI, 经处理得到钛铝硅酸盐复合材料(TiO₂/ASI). X射线衍射分析(XRD)和紫外-可见漫反射光谱(DRS)研究ASI对sol-gel方法制备TiO₂纳米晶形成过程和相转变的影响. 研究结果表明: 铝硅酸盐中间体不但能抑制TiO₂纳米粒子的团聚, 而且能够有效地抑制TiO₂由锐钛矿型向金红石型的相转变, 由此所制备TiO₂与ASI的钛铝硅酸盐复合材料(TiO₂/ASI)对溶液中亚甲基蓝的吸附性能高于单一的TiO₂或铝硅酸盐中间体.     

Controlled fabrication of TiO2 rutile nanorod/anatase nanoparticle composite photoanodes for dye-sensitized solar cell application

We present a straightforward procedure to prepare composite photoanodes which consisted of TiO2 rutile nanorods/anatase nanoparticles synthesized under hydrothermal conditions, with the ratio of rutile to anatase controlled simply by adjusting the volume of nitric acid. The as-prepared TiO2 composites exhibited high specific surface area, light-scattering effect, and good crystallinity. The dye-sensitized solar cells (DSCs) using the TiO2 composites showed higher short-circuit photocurrent and overall conversion efficiency than the DSC from pure-anatase nanoparticles. The highest conversion efficiency was achieved from the DSC based on TiO2 nanocomposites with 24 wt% rutile nanorods, which was attributed to improved light harvesting caused by the enhancement of specific surface area and scattering effect from rutile nanorods.