纳米TiO2光催化降解甲基橙

以TiOSO4为原料,制备了纳米TiO2粉末,经500度热处理后,XRD研究表明其为锐钛矿型TiO2;经TEM电镀观察,其粉末粒径大约为10nm左右,采用粘结剂法在玻璃板涂敷一层TiO2粉末,以甲基橙为研究对象,紫外灯为光源,研究了催化剂用量,甲基橙初始浓度,初始溶液pH值,光照强度对甲基橙脱色率的影响。     

六方介孔氧化硅负载磷钨酸的催化性能

采用浸渍法将磷钨酸(HPW)负载于六方介孔氧化硅(HMS)上,制备HPW改性HMS介孔材料HPW/HMS,对其进行了表征;以HPW/HMS为催化剂,催化2-萘甲醚(2-MN)与乙酸酐(AA)的酰化反应,考察了各因素对催化反应的影响. 结果表明,HPW高度分散在HMS上,HPW/HMS的酸量和酸强度随HPW负载量增加而增加. 在温度120℃、时间4 h、催化剂用量0.3 g及2-萘甲醚/乙酸酐摩尔比1:2条件下,2-萘甲醚转化率为75.3%(mol),目标产物2-甲氧基-1-萘乙酮的选择性达83.0%(mol). 催化剂可回收再利用,催化活性略有降低.     

纳米TiO_2光催化降解甲基橙

以TiOSO4为原料 ,制备了纳米TiO2 粉末 ,经 5 0 0℃热处理后 ,XRD研究表明其为锐钛矿型TiO2 ;经TEM电镜观察 ,其粉末粒径大约为 10nm左右 .采用粘结剂法在玻璃板涂敷一层TiO2 粉末 ,以甲基橙为研究对象 ,紫外灯为光源 ,研究了催化剂用量、甲基橙初始浓度、初始溶液 pH值、光照强度对甲基橙脱色率的影响     

纳米TiO_2的制备及其光催化性能

以钛酸四丁酯为原料,采用溶胶 凝胶法制备了纳米级TiO2颗粒,通过甲苯在样品上的光催化氧化过程评价了样品的光催化活性。考察了制备过程中的焙烧温度对样品颗粒的晶型、粒径和光催化性能的影响。X射线衍射结果表明,焙烧温度低于500℃时得到的样品都是锐钛矿型TiO2,700℃下得到的已基本是金红石型;随着焙烧温度的升高样品的粒径增大,光催化活性下降;甲苯在TiO2上的气相光催化氧化符合一级反应规律。     

Pt/TiO2介孔膜的制备及其光催化性能研究

以F127为介孔模板剂,钛酸异丙酯为前驱体,溶胶-凝胶法在载玻片上制备了TiO2介孔膜,用光还原法在TiO2膜表面沉积贵金属Pt,用SEM、XRD、XPS等对TiO2膜进行了表征。结果表明：TiO2膜具有介孔结构,为锐钛矿晶型,沉积在TiO2表面的Pt主要以单质形式存在。光催化结果表明介孔TiO2膜具有较高的光催化活性,表面沉积贵金属Pt后,光催化活性大大提高。     

TiO2纳米粒子膜垢表面态性质及其光催化活性的研究

TiO2纳米粒子膜催化剂光催化降解水中污染物,与粉末相比具有可重复使用、易回收等优点,近年来,在光化学领域受到人们的高度重视[1～3].膜催化剂的表面性质与其光催化活性直接相关,研究这些性质能够为研制、开发高效催化剂提供理论依据.本文采用TiCl4水解法,制备了酸性、碱性条件下TiO2纳米粒子膜.利用原子力显微镜(AFM)、X-射线衍射谱(XRD)、红外光谱(IR)和场诱导表面光电压谱(EFISPS)测定其表面微结构.考察了它们对苯酚降解的光催化活性,讨论了膜催化剂的表面性质对光催化活性的影响.     

Li^＋掺杂纳米TiO2的制备及其光催化性能研究

采用溶胶-凝胶法和浸渍法制备了Li^＋掺杂纳米TiO2光催化剂，并用XRD和TEM等技术进行了表征；用pH值漂移法测量了催化剂的零电位pH值（pHPZC）．结果表明，500℃煅烧制得的催化剂均为锐钛矿相；Li^＋的掺杂抑制了TiO2，粒子的生长，提高了催化剂的分散性；催化剂的零电位pH值为6．6—8．1，其值取决于Li^＋的浓度和掺杂方式．分别以紫外光和太阳光为光源，孔雀石绿和甲基橙为降解物评价了催化剂的光催化活性；并用气相色谱测试了污染物降解产生的CO2的含量．结果显示，对孔雀石绿的降解，浸渍法和溶胶-凝胶法掺Li^＋都能有效提高TiO2的光催化活性，但浸渍法比溶胶-凝胶法效果更好，催化活性最高的为浸渍法制备的5％（摩尔分数）Li^＋掺杂TiO2，其在紫外光和太阳光下的光催化活性分别比纯TiO2提高了6—8倍和9-10倍；对甲基橙的降解，除溶胶-凝胶法制备的3％（摩尔分数）Li^＋掺杂TiO2能稍提高光催化活性外，其它Li＇的掺杂都不同程度降低了TiO2的光催化活性；随污染物降解率的增加，最终降解产物CO2的含量增加．实验结果表明，Li^＋掺杂改变了催化剂表面的电荷状态从而改变了催化剂的零电位pH值是造成催化剂降解不同污染物具有不同催化活性的主要原因．     

水热法制备高比表面积介孔TiO2粉体及其光催化性能研究

实验以β环糊精(β-CD)为造孔剂,采用水热法制备了高比表面积介孔TiO2纳米粉体.利用BET、XRD、N2 ad-sorption-sorption等方法对样品进行了测试.考察了水热温度、水热时间、焙烧温度、造孔剂添加量等因素对材料的比表面积及其光催化性能的影响.实验结果表明:当体系的水热温度180℃、水热时间8h、...     

介孔TiO2的制备及染料敏化光催化制氢性能研究

文章利用CTAB为模板剂,以水热法制备介孔TiO2。并用虎红（Rose bengal）进行染料敏化制备了具有可见光活性的光催化剂,分别运甩UV-Vis、XRD、FT-IR和BET等手段对催化剂进行了表征,通过光解水制氢为反应模型考察了所制备催化剂的光催化活性。结果表明：用该方法合成的介孔TiO2具有较高的比表面和催化活性,活性顺序为：介孔TiO2〉P25〉溶胶凝胶捌备的TiO2（500℃煅烧）。     

Hexagonal Mesoporous Silica with Noodle-Like Shape

Hexagonal mesoporous silica (HMS) was prepared at ambient temperature by using dodecylamine (DDA) as the surfactant and tetraethyl orthosilicate (TEOS) as the silica precursor. The HMS materials were characterized by X-ray powder diffraction, N₂ adsorption/desorption, scanning electron microscopy and transmission electron microscopy. The samples prepared at various addition rates of TEOS and various alcohol/water (R/H) ratios were investigated. As the addition rate of TEOS decreased, the size of HMS particles increased and the textural porosity decreased. Non-alcoholic solution was required to prepare non-spherical particles. The HMS with noodle-like structures was prepared in the absence of alcoholic solvent. These noodle-like particles were about 0.1m in diameter and about submicrometer to several micrometers in length.     

Preparation of Spherical Hexagonal Mesoporous Silica

A series of hexagonal mesoporous silica (HMS) have been synthesized by the neutral assemble pathway in water-alcohol cosolvent systems, using dodecylamine (DDA) and tetraethyl orthosilicate (TEOS) as the starting materials. These materials were characterized with powder X-ray diffraction, nitrogen sorption measurement, differential thermal analysis, and transmission electron microscopy. The XRD patterns of these samples exhibited a strong intense reflection at low angle, suggesting the excellent mesostructures of the samples. The particle size of HMS decreased and the morphology of HMS exhibited high textural porosity as the HMS was prepared with high addition rate of TEOS. The particle size of HMS prepared without aging was smaller than that aged for 18 h, due to the reaction time of TEOS was not enough to form complete particles. Addition of NaCl and HCl hindered the formation of HMS mesoporous structure. In contrast, addition of 1-butanol did not affect the formation of HMS mesoporous structure. The sphereical HMS silica with uniform size has been synthesized by adjusting DDA and TEOS concentrations. The shape of HMS became larger and more spherical as the concentrate on of DDA decreased. The stirring rate of the reaction mixture had no effect on either the shape or the size of the spheroid HMS silicas. However, the particles started to crack at higher stirring rates.     

Fe-HMS的合成、表征及催化苯酚羟基化

以正硅酸乙酯(TEOS)、三氯化铁为原料,十二胺(DDA)为模板剂,采用溶胶-凝胶法合成了铁改性六方介孔硅分子筛(Fe-HMS),利用XRD、FTIR、UV-vis、ESR、TG-DTA、ESEM、TEM及N2吸附-脱附技术对材料结构进行了表征,同时以苯酚羟基化反应为探针考察了Fe-HMS的催化性能。结果表明,Fe-HMS材料由细小的球状纳米粒子组成,材料具有稳定的六方介孔结构,铁已进入六方介孔硅(HMS)载体的骨架;在苯酚羟基化反应中材料显示出较高的催化活性,苯酚的转化率最高可达46.9%,催化剂经450℃焙烧2 h即可再生,重复使用7次苯酚转化率仍可达36.4%。     

Characteristics of Gallium-Substituted Hexagonal Mesoporous Silica: Effects of Gallium Content

Gallium-substituted hexagonal mesoporous silicas (Ga-HMS) with various Si/Ga ratios in the range of 15 and 200 were prepared at ambient temperature by neutral surfanctant templating pathway. The materials were synthesized by using dodecylamine as a template and tetraethylorthosilicate as a silicon source. They were characterized by energy dispersive X-ray spectroscopy, powder X-ray diffraction (XRD), N₂ adsorption-desorption, thermogravimetric analysis, differential scanning calorimetry, scanning electron microscopy, transmission electron microscopy, Fourier-transform infrared absorption spectroscopy and ultraviolet-visible absorption spectroscopy. Ga-HMS samples had high surface areas and uniform mesoporous channels, which are similar to MCM-41. However, they differed from MCM-41 in presenting only a single peak in XRD patterns. They also possessed other characters of larger framework wall thickness, small crystallite domain sizes, and complementary textural mesoporosities in comparison with M41S materials. Ga-HMS materials had micropores and the hysteresis loops were obvious. These small crystallite size and complementary textural mesoporosity provided better access of the framework-confined mesopores. These mesoporous Ga-HMS samples exhibited irregularly shaped mesoscale fundamental particles which aggregated into larger particles. They also demonstrated better thermal stability than MCM-41. The textural pore volumes of Ga-HMS specimens could be up to 20 times as large as the framework volumes. The surfactant could be removed completely by calcination at 650^∘C. An absorption band of FT-IR at ca. 960 cm^–1 was assigned to the vibration of Si–O–Ga linkages. These samples also showed an absorbance band at 255 nm and 250 nm in UV-vis spectra. The results show that gallium was incorporated into the structure of HMS. The efforts in preparing Ga-HMS specimens by neutral-template synthesis route had led to new mesoporous silica molecular sieves with catalytically active gallium centers.     

纳米二氧化钛可见光催化活性的最新研究进展

文章综述了近年来研究二氧化钛可见光催化活性的最新进展。其中主要包括氧化物掺杂、金属离子掺杂、非金属掺杂、染料敏化、二氧化钛表面复合与衍生、半导体耦合等,同时探讨了各种不同掺杂改性的机理。最后,对提高二氧化钛的可见光催化活性的研究方向与前景进行了展望。     

Rapid Room Temperature Synthesis of Hexagonal Mesoporous Silica Using Inorganic Silicate Sources and Cationic Surfactants under Highly Acidic Conditions

The room-temperature synthesis of mesoporous silica was investigated by using cationic surfactants and inorganic Si sources, like sodium silicate and colloidal silica. Mesoporous silica analogous to the hexagonal MCM-41 could be obtained over a wide range of pH below ca. 11 within short synthesis time (3 h), when the Q⁴-state Si was absent in the Si source solution prior to mixing with an aqueous solution of cationic surfactants. It was suggested that the strongly acidic conditions (pH < 1) were favorable to give mesoporous silica materials with higher surface area and larger mesopore volume.     

纳米TiO2／玻璃微珠复合耐磨涂层的制备及其分形特征

在80℃下,以钛酸丁酯为原料,首先在酸性水溶液中利用胶溶–回流法在玻璃微珠表面制备了纳米级TiO2颗粒包覆层的纳米TiO2/玻璃微珠复合颗粒。通过扫描电镜、X射线衍射、X射线光电子能谱仪、BET（Brunauer–Emmett–Teller）法等检测手段对复合颗粒的表面形貌、包覆层相组成、比表面积等进行了表征。结果表明...     

ZnO/介孔SiO2组装体的制备和表征

在碱性条件下,以正硅酸乙酯和表面活性剂制备了球状的介孔二氧化硅,然后在减压的条件下用醋酸锌溶液浸渍,过滤干燥后在600℃下焙烧5 h制备出了球状的ZnO/介孔SiO2组装体,产物用XRD,TEM,BET,TG,IR进行了表征,结果表明介孔二氧化硅球上负载了ZnO纳米粒子。     

合成条件对气相法白炭黑性能的影响

以甲基三氯硅烷、氢气、空气为原料,制备气相法白炭黑。考察了原料配比、骤冷介质温度、合成炉温度、原料气速对白炭黑的比表面积、平均粒径的影响。结果表明：甲基三氯硅烷、氢气的量之比与白炭黑的比表面积成反比;合成炉温、骤冷介质温度与白炭黑的比表面积、平均粒径成反比;原料气速与白炭黑的比表面积成正比,与平均粒径成反比。较佳工艺为：甲基三氯硅烷、氢气与空气的量之比为0.33∶0.47∶1,冷却介质温度80～90℃,炉温800～850℃,气体流速5～6 m/s。