超临界流体干燥法制备TiO2/ Fe2O3 和TiO2/ Fe2O3/ SiO2 复合纳米粒子及光催化性能

以TiCl₄ 、Fe (NO₃ )₃·9H₂O 和Na₂SiO₃19H₂O 为原料, 采用溶胶凝胶法结合超临界流体干燥法(SCFD)制备了纳米级TiO₂/ Fe₂O₃ 和TiO₂/ Fe₂O₃/ SiO₂ 复合光催化剂。以光催化降解苯酚对所得催化剂的催化活性进行了评价。结果表明, 纳米TiO₂/ Fe₂O₃ 复合粒子与单组分TiO₂ 比较, 复合粒子光催化活性高于单组分的TiO₂, 6h 苯酚降解率高达95.9 %。SiO₂ 的加入可以抑制纳米粒子粒径的长大和晶相的转变, 增强TiO₂ 纳米粒子的热稳定性。复合光催化剂中Fe₂O₃ 最佳掺入量为0.06 %, SiO₂ 最佳掺入量为10 %(摩尔分数) 。并用XRD、TEM 和FTIR 等手段进行了表征。TiO₂ 以锐钛矿型形式存在, SiO₂ 以无定性形式存在。比较了不同制备方法制得的TiO₂/ Fe₂O₃ 复合光催化剂, 得出超临界干燥法制备的光催化剂具有粒径小、比表面积大、分散性好、光催化活性高等特点。采用超临界流体干燥可直接得锐钛型纳米复合光催化剂。     

Photocatalytic degradation of azo dyes using Au:TiO2, gamma-Fe2O3:TiO2 functional nanosystems

We report photocatalytic degradation studies on Navy Blue HE2R (NB) dye on significant details as a representative from the class of azo dyes using functional nanosystems specifically designed to allow a strong photocatalytic activity. A modified sol-gel route was employed to synthesize Au and gamma-Fe2O3 modified TiO2 nanoparticles (NPs) at low temperature. The attachment strategy is better because it allows clear surface of TiO2 to remain open for photo-catalysis. X-ray diffraction, Raman and UV-VIS spectroscopy studies showed the presence of gold and iron oxide phases along-with the anatase TiO2 phase. TEM studies showed TiO2 nanocomposite particles of size approximately 10-12 nm. A detailed investigation on heterogeneous photocatalytic performance for Navy Blue HE2R dye was done using the as-synthesized catalysts Au:TiO2 and gamma-Fe2O3:TiO2 in aqueous suspension under 8 W low-pressure mercury vapour lamp irradiation. Also, the photocatalytic degradation of Amranth and Orange G azo dyes were studied. The surface modified TiO2 NPs showed significantly improved photocatalytic activity as compared to pure TiO2. Exposure of the dye to the UV light in the presence of pure and gold NPs attached TiO2 catalysts caused dye degradation of about approximately 20% and approximately 80%, respectively, in the first couple of hours. In the presence of gamma-Fe2O3 NPs attached TiO2, a remarkable approximately 95% degradation of the azo dye was observed only in the first 15 min of UV exposure. The process parameters for the optimum catalytic activity are established which lead to a complete decoloration and substantial dye degradation, supported by the values of the Chemical Oxygen Demand (COD) approximately 93% and Total Organic Carbon (TOC) approximately 65% of the treated dye solution after 5 hours on the employment of the UV/Au:TiO2/H2O2 photocatalytic process.     

Photocatalytic removal of hazardous dye cyanosine from industrial waste using titanium dioxide

In this paper, photocatalytic degradation studies of a hazardous water soluble xanthene dye cyanosine in aqueous suspensions of titanium dioxide under a variety of conditions, viz., catalyst concentration, substrate concentration, pH, temperature and electron acceptor hydrogen peroxide (H2O2) have been reported. It was observed that photocatalytic degradation by TiO2 is an effective, economic and faster mode of removing cyanosine from aqueous solution. The optimum conditions for the degradation of the dye was dye concentration 1x10(-4)M, pH 8, catalyst concentration 0.04g/L and temperature +/-30 degrees C. Chemical oxygen demand and dye absorbance of the photodegraded dye solution substantially decreased.     

单晶TiN颗粒为前驱体制备TiO2薄膜及其光催化性能（英文）

为了开发高活性的二氧化钛(TiO2)光催化剂,通过简易的两步法制备了TiO2薄膜.首先将钛片放入氮化钛(TiN)纳米颗粒悬浮液中,然后干燥这一体系制得TiN/Ti薄膜,最后通过煅烧TiN薄膜前驱体制备了平整均一的二氧化钛(TiO2)薄膜.通过考察退火温度对样品光吸收性能的影响,确定最优退火温度为500℃.在此条件下制备的TiO2为多晶锐钛矿,吸收边带400 nm.以制备的TiO2薄膜为催化剂,3 h内苯酚的降解率达到88%,远大于使用德固赛TiO2(P25)时的62%,制备的二氧化钛薄膜比P25显示出更优良的光催化性能,其光催化降解苯酚的动力学常数为P25的2.2倍.     

TiO_2-Al_2O_3负载型催化剂的制备及其光催化性能

以钛酸四丁酯和氢氧化钠为反应物,采用两步水热法制备TiO2纳米线,并将其原位负载于Al2O3载体上,研究它们对甲基橙的光催化降解性能。结果表明,锐钛矿相TiO2主要呈纳米线和八面体状负载在Al2O3载体上,当TiO2负载质量分数为30%,焙烧温度为400℃,催化剂用量为1.332 0 g/L时,TiO2-Al2O3负载型催化剂光催化降解甲基橙的性能最佳,光照5 h后,甲基橙在紫外和太阳光下的降解率分别达到58.9%和55.6%。相同实验条件下,TiO2-Al2O3负载型催化剂对甲基橙的降解率比单纯TiO2提高了35.1%。     

Low-temperature Preparation of Photocatalytic TiO2 Thin Films on Polymer Substrates by Direct Deposition from Anatase Sol

Anatase TiO2 sol was synthesized under mild conditions （75℃ and ambient pressure） by hydrolysis of titaniumn-butoxide in abundant acidic aqueous solution and subsequent reflux to enhance crystallization. At room temperature and in ambient atmosphere, crystalline TiO2 thin films were deposited on polymethylmethacrylate （PMMA）, SiO2-coated PMMA and SiO2-coated silicone rubber substrates from the as-prepared TiO2 sol by a dip-coating process. SiO2 layers prior to TiO2 thin films on polymer substrates could not only protect the substrates from the photocatalytic decomposition of the TiO2 thin films but also enhance the adhesion of the TiO2 thin films to the substrates. Field-emission type scanning electron microscope （FE-SEM） investigations revealed that the average particle sizes of the nanoparticles composing the TiO2 thin films were about 35-47 nm. The TiO2 thin films exhibited high photocatalytic activities in the degradation of reactive brilliant red dye X-3B in aqueous solution under aerated conditions. The preparation process of photocatalytic TiO2 thin films on the polymer substrates was quite simple and a low temperature route.     

纳米TiO2光催化降解双酚A的研究

采用溶胶-凝胶法制备了纳米TiO2.以纳米TiO2为光催化剂,研究了在氧气存在条件下对典型内分泌干扰物质双酚A的光催化降解反应.分别讨论了分子氧、不同晶型、不同晶粒尺寸的纳米TiO2以及光照时间对双酚A降解反应的影响.结果表明,以0.2L/min的通氧速度进行光化学反应5h,锐钛矿型TiO2晶粒尺寸在10～20nm时对双酚A的光催化降解效率最好.     

Formation of hydrogen peroxide and degradation of phenol in synergistic system of pulsed corona discharge combined with TiO2 photocatalysis

In the present work, a synergistic system of pulsed corona discharge combined with TiO(2) photocatalysis has been developed to investigate the degradation rate of phenol solutions by varying experimental conditions of gas bubbling varieties (air, O(2), and Ar), solution pH values, and radical scavenger additives. The hydrogen peroxide (H(2)O(2)) concentration, which indicated the amount of hydroxyl radicals (OH) in the reaction system under different conditions of gas bubbling varieties and scavenger species, was also reviewed. The obtained results revealed that degradation efficiency of phenol could be increased by the addition of TiO(2) in pulsed discharge system. The gas of Ar and O(2) bubbled into the reaction system was found to be favorable for phenol degradation and H(2)O(2) formation. Both in air bubbling and in O(2) bubbling reaction system, the higher degradation rate of phenol occurred in the case of acidic solution. The addition of sodium carbonate or n-butanol in the solution displayed a negative effect for phenol removal, while the H(2)O(2) concentration showed different changing trend by adding different radical scavengers. The most effective degradation of the three main intermediates of catechol, 1,4-hydroquinone, and 1,4-benzoquinone formed during phenol decomposition existed in the synergistic system of pulsed corona discharge and TiO(2) photocatalysis bubbled with O(2).     

Photocatalytic degradation of methyl orange using a TiO2/Ti mesh electrode with 3D nanotube arrays

To further improve the photocatalytic techniques for water purification and wastewater treatment, we successfully prepared a new type of TiO(2)/Ti mesh photoelectrode, by anodization in ethylene glycol solution. The three-dimensional arrays of nanotubes formed on Ti mesh show a significant improvement in photocatalytic activity, compared to the nanotube arrays formed on foil. This can be demonstrated by about 22 and 38% enhancement in the degradation efficiency per mass and per area, respectively, when TiO(2)/Ti mesh electrode was used to photocatalyze methyl orange (MO). Furthermore, the effects of different parameters on MO photodegradation were investigated, such as different photoelectrode calcination temperature, the initial pH value of MO solution, and the present of hydrogen peroxide. The superior photocatalytic activity could be achieved by the TiO(2)/Ti mesh photoelectrode calcinated at 550 °C, due to the appearance of mixed crystal phases of anatase and rutile. In strong acidic or caustic conditions, such as pH 1 or 13, a high degradation efficiency can be both obtained. The presence of H(2)O(2) in photocatalytic reactions can promote photocatalytic degradation efficiencies. Moreover, the experimental results demonstrated the excellent stability and reliability of the TiO(2)/Ti mesh electrode.     

蝴蝶结状TiO2纳米粒子的制备及其光催化性能研究

以四甲基氢氧化铵（TMAOH）为结构导向剂,钛酸四丁酯（Ti（OBu）4）为钛源,低温水浴处理,再经180℃下水热晶化制备纳米TiO2,采用FT-IR、XRD、TEM、UV—Vis等测试手段对其结构和形貌进行表征,并通过苯酚的光催化降解实验测试其光催化性能,结果表明,TiO2为锐钛矿相,结晶度高,所得TiO2粒子为纳米棒,界面清晰,规整度高,经紫外光照6h后,对苯酚的降解率可达62．3％,具有较高的光催化活性。     

Investigation of photocatalytic removal and photonic efficiency of maxilon blue dye GRL in the presence of TiO2 nanoparticles

TiO₂ nanoparticles have been synthesized by solvent-free hydrothermal process. TiO₂ nanoparticles were annealed at 500°C for enhancing the characterization and the photocatalytic activity. The synthesized TiO₂ was characterized by x-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), atomic force microscopy (AFM), BET, and diffuse reflectance spectroscopy (UV-DR) techniques to study the morphology and structural configuration. The effects of different parameters such as the initial dye concentration, catalyst concentration, pH of the solution, light intensity, and reactive oxygen species (ROS) on relative photonic efficiencies and photocatalytic degradation kinetics of GRL were investigated, and the degradation of GRL follows pseudo-first order kinetics according to the Langmuir–Hinshelwood model. The ROS studies indicate that hydroxyl radicals and holes are the predominant reactive species within the same step, contributing up to 92.64%, hydroxyl radicals participate for about 55%, and holes share for about 37.64% in the photocatalytic degradation of GRL.     

TiO_2-Fe_3O_4/MIL-101(Cr)磁性复合光催化材料的制备及其光催化性能

采用原位水热法合成了TiO_2-Fe_3O_4/MIL-101(Cr)磁性复合光催化材料,利用XRD、SEM、UV-Vis DRS、BET和磁学测量系统对复合光催化材料的结构和性能进行了表征,并以亚甲基蓝(MB)为模拟污染物,研究了该复合光催化材料的可见光催化活性,并考察了光催化材料的稳定性。结果表明:巯基官能化的Fe_3O_4和TiO_2与MIL-101(Cr)结合成功,复合后的TiO_2-Fe_3O_4/MIL-101(Cr)光催化材料的可见光响应范围得到明显拓宽;当TiO_2的添加量为400mg时所制得的磁性复合光催化材料具有相对较好的光催化降解效果,经过120min光照后,对MB的去除率高达80%;该磁性复合光催化材料具有良好的稳定性和磁分离性能。     

Effect of deposition of Ag on TiO2 nanoparticles on the photodegradation of Reactive Yellow-17

Nanoparticles of TiO(2) were synthesized by sol-gel technique and the photodeposition of about 1% Ag on TiO(2) particles was carried out. Ag-deposited TiO(2) catalyst was characterised by XRD, TEM and UV-vis spectroscopy. The Ag-TiO(2) catalyst was evaluated for their photocatalytic activity towards the degradation of Reactive Yellow-17 (RY-17) under UV and visible light irradiations. Then the results were compared with synthesized nano-TiO(2) sol and P-25 Degussa and the enhanced degradation was obtained with Ag-deposited TiO(2). This enhanced activity of Ag-TiO(2) may be attributed to the trapping of conduction band electrons. The effect of initial dye concentration, pH and electron acceptors such as H(2)O(2), K(2)S(2)O(8) on the photocatalytic activity were studied and the results obtained were fitted with Langmuir-Hinshelwood model to study the degradation kinetics and discussed in detail.     

Sn~(4+)-TiO_2的制备及其光催化降解苯酚的研究

采用硬脂酸法制备出Sn4+-TiO2复合光催化剂,用透射电子显微镜和X光衍射仪对粉体的粒径、物相、形貌和热稳定性进行了表征。样品经500℃焙烧2h后,5%Sn4+-TiO2纳米粉末颗粒细小均匀,形状完整,粉末的平均晶粒度约为14nm。通过粉体对苯酚的降解情况对其光催化活性进行了测试,结果表明,与纯TiO2相比,Sn4+-TiO2的光催化活性有较大提高,当SnO2的掺入量为摩尔比5.0%时催化活性最高。以高压汞灯为光源,苯酚的初始浓度为80mg.L-1、催化剂5%Sn4+-TiO2投加量为1.0g.L-1时,溶液的pH为4,苯酚的光催化降解效果最好。     

碳纤维负载钐掺杂纳米TiO_2复合材料的制备与表征

采用静电纺丝法和热处理工艺制备了纳米碳纤维负载掺杂1.5%(摩尔分数)Sm的纳米Ti O2复合材料(Sm-Ti O2/CNFs),利用SEM、EDX、TEM、FTIR和XRD对其组成和结构进行了表征,并以甲基橙为降解对象,考察了Sm-Ti O2/CNFs复合材料在紫外光照射下对甲基橙的光催化降解效果。结果表明,掺杂Sm3+的Ti O2以锐钛矿晶型均匀分散在碳纳米纤维的表面和内部,质量分数为20%左右;相对于未掺杂的Ti O2/CNFs样品,Sm-Ti O2/CNFs的光催化活性提高约37%。     

TiO2-Al2O3复合光催化剂的制备及光催化性能

以Ti（SO4）2、Al2（SO4）3·18H2O为原料,采用乙醇助水热法制备了Al2O3-TiO2复合光催化剂,并通过改变A1／Ti物质的量之比、乙醇的体积分数、水热反应温度和反应时间等得到材料制备的最佳条件。XRD分析表明样品中的TiO2以锐钛矿晶相存在,SEM显示样品粒径范围在30-50nm之间。用最佳条件制备的复合光催化剂降解甲基橙溶液,反应30min后降解率这91％,降解过程符合一级动力学方程。     

Photodegradation of acetaminophen in TiO(2) suspended solution

This study investigated the photocatalytic degradation of acetaminophen (APAP) in TiO(2) suspended solution under a 250 W metal halide lamp. The influence of some parameters on the degradation of acetaminophen was studied and described in details, such as initial APAP concentration, initial pH value and TiO(2) dosage. After 100 min irradiation, about 95% of APAP is decomposed in the 1.0 g L(-1) TiO(2) aqueous solution with an initial concentration of 100 micromol L(-1). The effect of adsorption at three different pH values has also been analyzed and it has been conducted that pH 3.5, at which APAP was readily adsorbed also degraded at a faster rate. Reaction rate at pH 6.9 and pH 9.5 was 2.84 and 2.96 microM min(-1), respectively. Direct hole (h(+)) oxidation and ipso-substitution was found to be the main initial step for APAP degradation. Main reaction intermediates and products were identified by GC/MS analysis. The mechanism of acetaminophen photocatalytic degradation in TiO(2) suspended solution was studied not only experimentally but also theoretically by calculating the frontier electron density of APAP. The results obtained indicated that TiO(2) photocatalytic degradation is a highly effective way to remove APAP from wastewater and drinking water without any generation of more toxic products.     

Solvothermal synthesis of crystalline phase and shape controlled Sn(4+)-doped TiO2 nanocrystals: effects of reaction solvent

The Sn(4+)-doped TiO(2) nanocrystals with controlled crystalline phase and morphology had been successfully prepared through easily adjusting the solvent system from the peroxo-metal-complex precursor by solvothermal method. The Sn(4+)-doped TiO(2) nanocrystals were characterized by XRD, Raman, TEM, HRTEM, XPS, ICP-AES, BET, and UV-vis. The experimental results indicated that the Sn(4+)-doped TiO(2) nanocrystals prepared in the pure water or predominant water system trend to form rodlike rutile, whereas the cubic-shaped anatase Sn(4+)-doped TiO(2) nanocrystals can be obtained in the alcohol system. The growth mechanism and microstructure evolution of the Sn(4+)-doped TiO(2) nanocrystals prepared in the different solvent systems are discussed. The liquid-phase photocatalytic degradation of phenol was used as a model reaction to test the photocatalytic activity of the synthesized materials. It was found that sample Sn(4+)-doped TiO(2) prepared in 1-butanol showed the maximum photoactivity, which attributed to higher band gap, optimal crystalline phase and surface state modifications.     

Preparation and characterization of visible-light-driven TiO2 photocatalyst Co-doped with nitrogen and erbium

A series of nitrogen and erbium co-doped TiO2 photocatalyst was prepared by sol-hydrothermal method. The structure and properties of the photocatalyst were characterized by X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) method, X-ray photoelectron spectroscopy (XPS), and UV-vis diffuse reflectance spectra (DRS). The XRD and BET results showed that co-doping inhibited the increase of crystallite size and enlarged specific surface areas. XPS spectroscopy indicated nitrogen atoms were incorporated into TiO2 lattice, and erbium atoms mostly existed in the forms of Er2O3. A shift of the absorption edge to the lower energy and four absorption bands located at 654, 544, 524 and 489 nm attributed to the 4f transitions of 4I15/2 --> 4F2/9, 4I15/2 --> 4S3/2, 4I15/2 --> 2H11/2, 4I15/2 --> 4F7/2 of Er3+ were observed using DRS spectroscopy. The catalytic efficency was evaluated by the photocatalytic degradation of methyl orange (MO) under visible light irradiation. The results showed that the photocatalytic performance of the co-doped TiO2 was related with the hydrothermal temperature and the molar ratio of N/Ti, and they showed higher acitivites than pure TiO2. Results determined by fluorescence technique revealed that irradiation (lambda > 400 nm) of TiO2 photocatalyst dispersed in MO solution induces the generation of the highly active hydroxyl radicals (OH). It indicated the photocatalytic activities of TiO2 photocatalyst were correlation with the formation rate of hydroxyl radicals (OH) and other active oxygen species.     

TiO2／海泡石催化剂的光催化降解性能

以钛酸四丁酯为前驱体,采用水解．沉淀法制备纳米TiO2,再将其负载于海泡石上制得TiO2/海泡石催化剂,用X射线衍射和扫描电子显微镜对载体催化剂的形貌及晶型进行了分析．以紫外光为光源,在水溶液中以环境激素邻苯二甲酸二乙酯（DEP）为降解底物进行光催化性能的研究．结果表明：催化剂的用量和TiO2的负载量对光催化降解速率都有影响．其中TiO2/海泡石催化剂的用量起主要作用,更能影响其光催化速度及DEP的降解．当催化剂用量为4g/L、TiO2负载量为30％时,TiO2/海泡石催化剂的催化效果较好．