大比表面积钛黑颜料的制备和表征

本文首次通过pH值控制沉淀法制备前驱物丁二酸钛肼复盐,并进一步热分解制备大比表面积钛黑颜料-黑色钛氧化物。通过比表面积(BET)、电子能谱(EDS)、X射线光电子能谱分析(XPS)、X射线粉末衍射(XRD)、场发射扫描电子显微镜(HRSEM)、物理吸附仪、激光粒度仪和Color i5型台式分光测色仪对黑色钛氧化物进行了表征,确定了黑色钛氧化物的组成为2TiO2·Ti2O3,其表面积为53.854 4 m2·g-1。并考察了酸源、水合肼用量、酸钛比、反应时间、pH、NaOH浓度和煅烧温度等各种反应参数对黑色钛氧化物的颗粒尺寸、分布均匀性和黑色度的影响。用元素分析仪和等离子体光谱仪测定了前驱物组成,确定其组成为[Ti(C4H4O4)2]0.85·2Ti2O3·6N2H4·3H2O,并探讨了黑色钛氧化物形成机理,为新型混合价材料黑色钛氧化物的制备提供重要参考依据。     

介孔TiO2的水热法制备及其光催化性能

以二钛酸钾(K2Ti2O5)经离子交换得到的无定形水合二钛酸(H2Ti2O5·xH2O)为原料,与葡萄糖溶液在220℃下进行水热反应,再在空气中520℃焙烧,制备出介孔TiO2.用扫描电子显微镜(SEM)、X射线衍射(XRD)、N2吸附、透射电子显微镜(TEM)等技术对样品进行了表征.结果表明,该介孔TiO2具有微米级棒状或针状形貌,晶粒大小为12.3 nm,比表面积为106 m2·g-1,孔容为0.31 cm3·g-1,孔径为8.06 nm,焙烧处理后晶型仍是锐钛矿相.水热生成的碳抑制了晶粒的团聚生长和晶型的转变,提高了介孔TiO2的热稳定性.甲基橙降解实验评价了介孔TiO2的光催化性能,结果发现其活性与商用TiO2催化剂P25相当,而其较大的粒径更容易回收再利用.以碘化钾为探针反应,表明介孔TiO2的光催化机制以光生空穴氧化为主.     

水热法制备二氧化钛微球的形貌控制及机理研究

以钛粉、Na OH和H2O2为原料,采用水热法成功制备出二氧化钛微球。利用X-射线粉末衍射仪(XRD)、扫描电子显微镜(SEM)和场发射扫描电镜(FESEM)对产物的结构、形貌和尺度进行了表征。结果表明,产物为金红石型Ti O2,微球的直径约为1~2μm,微球由许多纳米管组成。根据实验结果,讨论了二氧化钛纳米管的生长机理,初步研究了双氧水用量,水热温度以及煅烧温度等对产物形貌形成的影响。     

Bi2Ti2O7薄膜的自组装法制备及表征

以Bi(NO3)3·5H2O和Ti(OC4H9)4为原料,采用自组装单层膜技术,在负载有功能化三氯十八烷基硅烷(octadecyl-trichloro-silane,OTS)的FTO基板上制备了Bi2Ti2O7薄膜。基板表面的亲水性测试表明,紫外照射使OTS自组装单层膜表面由疏水转变为亲水,实现功能化。借助X射线衍射(XRD)、X射线能量色散谱(EDS)、扫描电子显微镜(SEM)和原子力显微镜(AFM)分析分别对Bi2Ti2O7薄膜的组成、结构和微观形貌进行了表征。结果表明,沉积溶液浓度为0.02 mol·L-1时,所得Bi2Ti2O7薄膜均匀致密。560℃热处理1 h、厚度为0.4μm的Bi2Ti2O7薄膜在100 kHz的介电常数为153,介电损耗为0.089。     

硫掺杂钛酸(盐)纳米管的表征与可见光光催化活性

以二硫化钛为钛源和硫源,通过与NaOH水热反应成功制备了硫掺杂钛酸(盐)纳米管。 采用X射线衍射、高分辨透射电子显微镜、扫描电子显微镜、扩展X射线吸收精细结构(EXAFS)和X光微区分析等手段对所制备的硫掺杂钛酸(盐)纳米管的结构、形貌、硫掺杂状态和掺杂量进行了表征,并以可见光光催化氧化乙醇反应为探针,采用原位气相色谱技术研究了硫掺杂钛酸纳米管的可见光光催化活性;结果表明,S原子以S2-形式取代了钛酸纳米管骨架中O原子的位置, 有效实现了硫掺杂;硫掺杂钛酸(盐)纳米管壁厚平均尺寸为2.9 nm,管径平均尺寸为9.7 nm。 可见光光催化氧化乙醇反应结果表明,掺硫钛酸纳米管在极低的掺硫量条件下,表现出比未掺杂的二氧化钛纳米管具有更高的可见光光催化活性。     

二氧化钛涂覆多壁碳纳米管的制备及可见光催化活性

以多壁碳纳米管(MWCNTs)为反应性模板, 金属钛粉为钛源, 采用熔盐法制备碳化钛涂覆的MWCNTs中间体, 然后通过控制氧化制备二氧化钛涂覆的MWCNTs复合光催化剂. 考察了熔盐反应温度、MWCNTs和钛粉的摩尔比及氧化温度等对产物的结构和形貌的影响. 采用X射线衍射(XRD)、场发射扫描电子显微镜(FE-SEM)、透射电子显微镜(TEM)和X射线光电子能谱(XPS)等技术对其进行了系统的表征; 以亚甲基蓝(MB)溶液的脱色降解为模型反应, 考察了催化剂的可见光(λ>420 nm)催化活性. 结果表明: 所制备的催化剂基本保持了原始MWCNTs的纤维状形貌, 二氧化钛涂层在MWCNTs表面分布均匀, 并与MWCNTs之间结合紧密, 形成了Ti－O－C键. MWCNTs增强了污染物亚甲基蓝在催化剂表面的吸附, Ti－O－C键的形成使得在二氧化钛价带附近形成了杂质能级, 提高了对可见光的吸收和利用, 因此所制备的TiO₂/MWCNTs复合光催化剂表现出较高的可见光催化活性.     

阴极等离子体电解法制备氧化铝纳米颗粒

以金属铝为阴极材料,以3mol·L-1浓度的NH4NO3水溶液为电解液,采用非对称电极阴极等离子体电解方法制备出氧化铝纳米颗粒.采用扫描电子显微镜(SEM)、透射电子显微镜(TEM)、X射线能量色散谱(EDX)、X射线衍射(XRD)和X射线光电子能谱(XPS)对颗粒的形貌和结构进行了表征.结果表明颗粒以立方相Al2O3为主.还对放电过程的电流变化和发光现象进行了研究.结合实验结果提出了这种颗粒的生长机制.     

银负载量对网状TiO_2柔性薄膜电极储锂性能的影响

采用水热法结合银镜反应制备出一系列不同Ag负载量(2.2%、4.0%、6.4%,w/w)改性的3D纳米网状结构Ag@Ti O2薄膜电极。利用电感耦合等离子体技术(ICP)、X射线衍射(XRD)、扫描电镜(SEM)、透射电镜(TEM)和X射线能谱(EDX)等表征手段测试所合成材料的形貌及成分,实验结果表明Ag纳米颗粒可以成功沉积在Ti O2纳米线表面。电化学测试数据则表明,4.0%(w/w)负载量的Ag@Ti O2相比于未改性和其他负载量的Ti O2纳米线具有更好的倍率性能和更稳定的可逆容量。在50,100,200,400,800和1 200 m A·g~(-1)的电流密度条件下,该改性电极的放电容量可分别达到261.4,253.7,239.5,216.5,193.1和185.1 m Ah·g~(-1),在200 m A·g~(-1)下循环80次后容量保持率仍能达到99.8%。     

介孔TiO2的水热法制备及其光催化性能

以二钛酸钾(K2Ti2O5)经离子交换得到的无定形水合二钛酸(H2Ti2O5·xH2O)为原料, 与葡萄糖溶液在220 ℃下进行水热反应, 再在空气中520 ℃焙烧, 制备出介孔TiO2. 用扫描电子显微镜(SEM)、X射线衍射(XRD)、N2吸附、透射电子显微镜(TEM)等技术对样品进行了表征. 结果表明, 该介孔TiO2具有微米级棒状或针状形貌, 晶粒大小为12.3 nm, 比表面积为106 m2·g-1, 孔容为0.31 cm3·g-1, 孔径为8.06 nm, 焙烧处理后晶型仍是锐钛矿相. 水热生成的碳抑制了晶粒的团聚生长和晶型的转变, 提高了介孔TiO2的热稳定性. 甲基橙降解实验评价了介孔TiO2的光催化性能, 结果发现其活性与商用TiO2催化剂P25相当, 而其较大的粒径更容易回收再利用. 以碘化钾为探针反应, 表明介孔TiO2的光催化机制以光生空穴氧化为主.     

基于MWCNT/TiO2对电极和硫醇盐/二硫化物非碘氧化还原电对的染料敏化太阳能电池性能

采用水热法合成出多壁纳米碳管/二氧化钛(MWCNT/TiO₂)复合物, 并作为染料敏化太阳能电池(DSSC)中对电极材料并组装成电池. 通过场发射扫描电子显微镜(FE-SEM)、傅里叶变换红外(FTIR)光谱、X射线粉末衍射(XRD)、同步热重-差示扫描量热(TGA-DSC)、拉曼(Raman)光谱和光电子能谱(XPS)等方法对其形貌、组成和结构进行表征. 结果表明, 酸化MWCNT表面―COOH与水热生长出的锐钛矿TiO₂表面―OH之间, 通过形成类似于O＝C―O―Ti 或者C―O―Ti 的结构, 能有效地增强复合物薄膜层与导电玻璃基底之间的相互作用. 通过循环伏安(CV)、电化学阻抗谱(EIS)、塔菲尔曲线(Tafel)和电池的伏安特性曲线等方法研究了该类对电极对硫醇盐/二硫化物(T-/T₂)非碘氧化还原电对的光电化学特性. 结果表明: 当MWCNT与TiO₂质量比为3:1时, 基于该复合物对电极与T-/T₂非碘氧化还原电对所组装DSSC的开路电压为0.63 V, 短路电流为15.81 mA·cm^-2, 填充因子为0.65, 光电转换效率达到6.47%.     

Hydrothermal synthesis and characterization of nanorods of various titanates and titanium dioxide

The formation process of titania based nanorods during hydrothermal synthesis starting from an amorphous TiO2.nH2O gel has been investigated. Sodium tri-titanate (Na2Ti3O7) particles with a rodlike morphology were prepared by a simple hydrothermal process in the presence of a concentrated NaOH aqueous solution. The ion exchange reaction of the synthesized Na2Ti3O7 nanorods with HCl under ultrasonic treatment promotes a complete sodium substitution and the formation of H2Ti3O7 nanorods. Low-temperature annealing of the as-produced nanorods of Na2Ti3O7 and H2Ti3O7 leads to a loss of the layered crystal structure and the formation of nanorods of condensed framework phases-sodium hexa-titanate (Na2Ti6O13) and metastable TiO2-B phases, respectively. These transformations proceed without a significant change in particle morphology. The nanostructures were investigated by scanning electron microscopy (SEM), powder X-ray diffraction (XRD), the Brunauer-Emmett-Teller (BET) method, thermogravimetric analysis (TGA), and Raman spectroscopy. The structural defects of the synthesized nanorods were investigated by high-resolution electron microscopy. The presence of planar defects can be attributed to the exfoliation of the zigzag ribbon layers into two-dimensional titanates as well as to the condensation of the layers of TiO6 octahedra into three-dimensional frameworks.     

水热法合成高功率锂离子二次电池用球形Li4Ti5O12负极材料

以球形TiO2和LiOH溶液为反应物,通过水热法合成了尖晶石型Li4Ti5O12,并使用X射线衍射(XRD)、傅里叶变换红外(FTIR)光谱、扫描电镜(SEM)和激光粒度分布(PSD)对其结构、形貌和电化学性能进行了表征.结果表明:通过该法得到的产品颗粒大小均匀,粒度分布狭窄,结构与标准Li4Ti5O12谱图一致.实验选定温度下所得的Li4Ti5O12均表现出良好的电化学性能.其中,800°C热处理所得样品的电化学性能最好,室温下,以35mA·g-1的电流密度进行充放电,其可逆容量达到162mAh·g-1,同时这种材料也表现出良好的倍率性能,即使在720mA·g-1的电流密度条件下进行充放电,其可逆容量仍可达到124mAh·g-1.     

溶胶-凝胶-水热晶化法制备锐钛矿TiO2纳米膜的耐蚀性能

以钛酸正丁酯为前驱体, 采用溶胶-凝胶-水热晶化法在不锈钢(SS)表面制备TiO₂纳米膜. 利用X射线衍射(XRD)、Raman光谱、场发射扫描电子显微镜(SEM)、原子力显微镜(AFM)和俄歇电子能谱(AES)表征了TiO₂纳米膜的晶型、表面形貌和表面化学组成. 通过极化曲线和电化学阻抗谱(EIS)研究了TiO₂纳米膜的耐蚀性能. 170 °C下水热晶化制备的锐钛矿TiO₂与450 °C焙烧制备的锐钛矿TiO₂的结晶度类似, 但两种TiO₂薄膜的表面结构存在明显差异, 水热晶化法制备的TiO₂纳米膜在3.5% (w) NaCl溶液中的耐蚀性能优于焙烧法制备的.     

Ag负载TiO2纳米管微波辅助水热法制备及其光催化性能

以微波辅助水热法制备了二氧化钛纳米管,然后通过浸渍法在其表面负载了银纳米颗粒.所得样品用X射线衍射(XRD)、扫描电镜(SEM)、透射电镜(TEM)、氮吸附、X射线光电子能谱(XPS)、紫外-可见漫反射等测试方法表征.微波加热处理可以大大缩短反应时间,产物为无定型纳米管,经高温焙烧后转变成锐钛矿型二氧化钛.所得纳米管的外径为7-8 nm,内径为5-6 nm,管长约200 nm,比表面积可达371 m2·g-1.负载的银分散在纳米管的表面,对纳米管的结构与晶型没有影响,但是拓宽了二氧化钛的光吸收范围,使吸收边红移至可见光区,并且有效抑制了光生电子空穴的复合.在可见光降解罗丹明B的实验过程中,与Ag负载的P25及纯二氧化钛纳米管相比,Ag负载二氧化钛纳米管具有更高的可见光催化活性,并且当Ag/Ti 物质的量的比为0.5%时,可见光催化性能最好.     

Zn3(OH)2V2O7·2H2O纳米片的水热制备

采用硝酸锌、五氧化二钒和氢氧化钠作为反应物,通过一个简单的CTAB辅助的水热方法制备了Zn3(OH)2V2O7·2H2O纳米片.运用XRD,ICP-AES,FTIR,HRTEM,EDS,FE-SEM对产物的晶相和形貌进行了表征.结果表明CTAB在控制产物的形貌、尺寸分布和自组装过程中起着关键作用.同时我们研究了产物的晶体生长行为和自组装过程.     

Preparation and Characterization of Cu3V2O7(OH)2·2H2O Hollow Spheres from NazV6O16·3HzO Nanobelts

Monoclinic Cu3V2O7(OH)2·2H2O(copper polyvanadate) hollow spheres were prepared with Na2V6O16·3H2O nanobelts as V-precursor by hydrothermal method.The purity and structure of the products were characterized by X-ray powder diffraction(XRD),Fourier transform infrared(FTIR) spectroscopy,Raman spectroscopy,thermogravimetric analysis(TGA) and X-ray photoelecton spectroscopy(XPS).The morphology and size were observed by scanning electron microscopy(SEM).We found that the Kagomé staircase-structural copper polyvanadate hollow spheres with an average diameter of 7 μm could be easily synthesized via the reaction of Na2V6O16·3H2O nanobelts with sufficient copper sulfate.The dielectric property of the copper polyvanadate demonstrates that dielectric loss hardly changes when the frequency of applied electric field is higher than 100 kHz.The formation process of the hollow spheres is discussed in detail by the observation of a series of products prepared for different reaction time.     

Doping Effect on the Grain Growth of Spinel LiMn2O4 Prepared by Sol-Gel Methods

The cathode-active materials, Li1+yMxMn2-xO4 (M = Al, Co, Ni, Zn, y = 0.02, x = 0.02) powder, were synthesized by sol-gel method using LiOH, Mn(NO3)2 as the starting materials, citric acid as a carrier and Al(NO3)3·9H2O or Co(NO3)2·6H2O or Ni(NO3)2·6H2O or Zn(NO3)2·6H2O as dopants. The influence of different doping elements on the structural properties of the as-prepared samples was investigated by X-ray diffraction (XRD), infrared (IR) spectroscopy and scanning electron microscopy (SEM). X-ray diffraction patterns of the prepared samples were identified as the spinel structure with space group Fd3m. The grain size increases gradually as the sintering temperature rises and corresponding activation energies for the grain growth have been estimated using Arrhenius’ empirical relation.     

MgFe2O4纳米粉体的水热合成及其表征(英)

MgFe₂O₄ nanoparticles were hydrothermally synthesized at 150 ℃ using iron nitrate [Fe(NO₃)₃·9H₂O], magnesium nitrate [Mg(NO₃)₂·6H₂O] and sodium hydroxide (NaOH) as starting materials by carefully controlling the reaction conditions. The influences of several factors such as presence or absence of Na⁺, molar ratio of Fe³⁺ / Mg²⁺, concentration of mental ions, temperature and reaction time on resultant products were investigated in the hydrothermal process. The sample was characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM), and its magnetic properties were measured using vibrating sample magnetometer (VSM).     

Formation of crystalline Na2V6O16·3H2O ribbons into belts and rings

Single-crystalline nanobelts and nanorings of Na(2)V(6)O(16)·3H(2)O structures have been facilely synthesized through a direct hydrothermal reaction between NaVO(3) and H(3)PO(4), without the addition of any harmful solvents or surfactants. The analytical techniques of scanning electron microscopy, transmission electron microscopy (TEM), powder X-ray diffraction, thermogravimetric analysis, energy-dispersive X-ray spectroscopy, Fourier transform infrared, high-resolution TEM, and selected-area electron diffraction have been used to characterize the morphology, composition, and structure of the synthesized products. The Na(2)V(6)O(16)·3H(2)O nanobelts are up to several hundreds of micrometers in length and 100-300 nm in thickness, and for nanorings, the diameters are 4.5-6.5 μm. H(3)PO(4) plays a key role in maintaining the pH of the solution as well as producing PO(4)(3-) ions in solution. The chemical reactions and a possible growth mechanism involved in the formation of Na(2)V(6)O(16)·3H(2)O nanobelts and nanorings are briefly discussed.     

泡沫镍载 NiCO2O4电极的制备及其催化 H2O2电氧化的性能

本文以水热法结合热处理法原位制备了泡沫镍载 NiCo₂O₄纳米线电极,使用XRD、SEM和TEM对合成的 NiCo₂O₄纳米线进行了表征,NiCo₂O₄纳米线直径约80 nm,长度约 3 ~ 5 μm. 使用循环伏安和计时电流法测试了泡沫镍载NiCo₂O₄纳米线催化H₂O₂的电氧化性能,结果表明泡沫镍载NiCo₂O₄纳米线对H₂O₂电氧化有着优良的催化活性、稳定性和传质性能,在0.3 V电位下0.4 mol·L ^-1 H₂O₂和2 mol·L ^-1 NaOH溶液中氧化电流可达380 mA·cm ^-2.