微乳液法制备纳米硫化锌及其光催化性能的研究

以四元体（十六烷基三甲基溴化铵/水/正辛烷/正丁醇）W/O型微乳体系为介质,制备了纳米硫化锌粉体,利用X射线衍射仪、透射电镜对硫化锌粉体进行表征.研究了硫化锌粉体光催化降解次甲基蓝的能力.结果表明,该微乳体系稳定,所得硫化锌粉体平均粒径为50 nm,在紫外光、太阳光照射下1 h,对次甲基蓝的最大降解率分别为83%和79%.     

声化学制备纳米光催化材料研究进展

较为系统地介绍了近年来利用声化学制备纳米结构光催化材料的研究状况,综述了具有纳米结构的金属氧化物、金属硫化物、金属盐、复合物、介孔材料等光催化材料方面的声化学合成研究的最新成果.认为声化学合成具有温度低、操作简单的特点,对制备新颖结构的纳米光催化材料具有重要的作用.     

二氧化钛薄膜制备技术及其光催化性能的应用

二氧化钛薄膜以其优异的光催化性能受到广泛关注。本文介绍了几种常见的制备二氧化钛薄膜的方法(溶胶-凝胶法,物理气相沉积法,化学气相沉积法)以及目前新型的二氧化钛薄膜的制备技术-机械球磨技术。此外,总结了二氧化钛薄膜光催化特性在污水处理、空气净化、杀菌消毒、防雾和自清洁作用方面的应用,并对未来发展进行展望。     

氧化锌的制备及其光催化性能研究

本文以醋酸锌和氢氧化钠为原料,以聚乙二醇(PEG)作为活性剂,水热法制备出粒径均匀的氧化锌,采用扫描电镜(SEM)、X射线衍射(XRD)对ZnO的形貌、结构进行了表征,以纳米氧化锌作为光催化剂对有机染料罗丹明B进行了光催化降解实验,结果表明,制备的ZnO具有良好的光催化性能.     

CeO2纳米晶的制备及其光催化活性的研究

以硝酸稀土为原料，碳酸氢铵作沉淀剂，乙二醇、丙三醇、聚乙二醇1000和PVA为分散剂，通过控制一定的反应条件，制得易沉降、过滤的水合碳酸铈，此前驱物在一定温度下焙烧即可得到CeO2纳米晶。通过X射线衍射、扫描电镜、紫外可见分光光度计等分析测试方法研究了CeO2纳米晶的形成过程、微观形貌、粒度及光吸收特性。结果表明：此前驱物在400℃以上焙烧，即可得到立方相CeO2纳米晶，分散剂的种类和焙烧温度对CeO2纳米晶的粒度、分散性及光催化活性均有一定的影响。在适宜条件下，CeO2纳米晶可使染料酸性黑10B的脱色率达98％以上。     

溶胶-凝胶法制备TiO2及其光催化性能的研究

以钛酸丁酯为原料、无水乙醇为溶剂、硝酸为抑制剂,运用正交试验法确定了溶胶-凝胶法制备TiO2的初步最优条件,运用X-射线衍射技术对所制备的TiO2粉体样品进行了表征,并以大红染料作为目标降解物,研究了制备TiO2粉体活化温度、活化时间、紫外灯照射高度、催化剂投加量以及废水pH值对光催化性能的影响.结果表明,该方法制备的TiO2为纳米级锐钛矿.制备TiO2的最佳配比条件为:无水乙醇20.0 ml,蒸馏水1.5 ml,pHl.7.当活化温度为450℃、活化时间为180 min、紫外灯照射高度为10 cm、催化剂投加量为2g/L、目标废水pH为4.0时,达到最佳降解效果.     

Ag/BiOCl复合纳米薄膜的合成及光催化性能研究

研究了贵金属Ag修饰对新型半导体BiOCl薄膜材料光催化性能的影响.采用溶胶-凝胶浸渍提拉法先在ITO玻璃上制备了BiOCl薄膜.以其为基底用磁控溅射方法沉积少量的Ag制备Ag/BiOCl复合纳米薄膜.分别研究了不同沉积时间和溅射气压,以及后处理温度下获得的Ag/BiOCl薄膜对罗丹明B(Rh B)染料在紫外光下的光催化降解活性.结果发现适量的Ag修饰能够提高BiOCl薄膜的光催化活性.通过实验探索,当制备金属Ag的优化参数为溅射压强1 Pa,溅射时间1 s,后处理温度200℃,时间1h时获得的Ag/BiOCl复合纳米薄膜具有最好的光催化性能.用XRD,SEM,UV-Vis光谱等测试方法对其结构、形貌、光谱吸收性等进行了测量分析.进一步探讨了适量贵金属沉积对BiOCl薄膜光催化活性提高的可能原因,杂质能级形成的肖特基势垒对电子有捕获陷阱作用从而增加电子-空穴对的分离,同时利于光生载流子的重新分布.     

TiO2／活性炭的制备与光催化性能

以活性炭(AC)为载体，采用Sol-Gel法制备纳米TiO2／AC复合催化剂，利用SEM，TG-DTA，XRD等对其组成、结构、尺寸等进行分析和表征；并用紫外灯为光源，通过可溶性罗丹明B的光催化降解反映对其光催化活性进行研究。结果表明，TiO2纳米粒子的尺寸范围在30nm～60nm之间，其中TiO2的晶型主要为锐钛矿；活性炭载体与TiO2结合牢固，TiO2纳米颗粒不发生二维粘结；TiO2／AC复合体的比表面积比活性炭载体的大，对罗丹明B在200min内达到完全降解，而P25需要5h，TiO2／AC复合体具有很强的光催化活性，并且制备的TiO2／AC复合体催化剂容易从溶液中分离。     

正交相三氧化钨的制备及其光催化次甲基蓝性质研究

通过低温水热法和微乳液法,成功合成了正交相三氧化钨纳米片,利用X-射线衍射(XRD),场发射扫描电镜(FESEM),热重分析(TGA)对合成的样品进行了表征.将所得样品作为催化剂,以有机染料次甲基兰为模型,进行了光催化降解实验研究.探讨了催化反应的影响因素,测试了催化剂的稳定性,并对光催化降解产物进行了分析.结果表明,次甲基蓝在日光照射下分解为Cl-、SO42-、NO3-等无机离子,显示了正交相三氧化钨纳米片在光催化脱色含氮染料废水方面具有潜在应用价值.     

水热法制备WO3纳米棒阵列及其光催化性能

采用水热法,以Na₂WO₄·2H₂O为原料,NaCl为添加剂,直接在氧化铟锡透明导电基底上制备了有序WO₃纳米棒阵列.利用X射线衍射、扫描电子显微镜、透射电子显微镜和高分辨透射电子显微镜等手段对制备的纳米棒进行了表征,考察了pH值对产物形貌、尺寸和取向性的影响.结果表明：单根WO₃纳米棒具有六方单晶结构,随着前驱液pH值的增大,平行于基底生长的WO₃纳米棒捆逐渐转变为垂直于基底生长的纳米棒阵列.另外,对制备得到的两种不同取向的WO₃纳米棒结构进行了光催化降解甲基蓝溶液的研究,发现相比于WO₃纳米棒捆结构,纳米棒阵列的光催化性能更高.     

水热法制备稀土掺杂纳米TiO_2薄膜及光催化降解性能研究

以Ti(SO4)2水溶液为前驱物,尿素为沉淀剂,采用水热法在玻璃基片上制备了稀土离子掺杂的TiO2薄膜。以薄膜对紫外光吸收值为指标,考察了水热反应时间、镀膜次数、掺杂稀土离子的种类、掺杂量对紫外光吸收性能的影响,确定了掺杂薄膜最佳制备条件:在1.0mol/L尿素溶液中,温度为160℃,反应10h,镀膜两次,稀土最佳掺杂量为n(La)=0.9%或n(Eu)=1.1%(n为摩尔比),掺镧元素的效果好于掺铕元素。利用X射线衍射仪(XRD)、扫描电子显微镜(SEM)对所制备的TiO2薄膜的相结构及形貌进行了分析和表征,结果表明,所制备的薄膜均匀、致密、无可视缺陷。以甲基橙为光催化降解的探针化合物,探讨了TiO2薄膜光催化降解性能,结果表明,掺杂稀土离子的TiO2薄膜对光催化降解性能远优于未掺杂的TiO2薄膜。     

Synthesis and photocatalytic performance of europium-doped graphitic carbon nitride

Europium-doped graphitic carbon nitride was synthesized by an easy method and characterized by X-ray diffraction （XRD）, ultraviolet-visible diffuse reflection spectroscopy （UV-Vis DRS）, Fourier transform infrared spectroscopy （FTIR）, photolu- minescence spectra （PL） and transmission electron microscopy （TEM）. The effect of dopant concentration on the rate of photocata- lytic degradation was investigated through degrading methylene blue aqueous solution. The results indicated that the europium-doped samples all possessed increased photocatalytic activity and the optimal europium content was 0.38 wt.%. Moreover, a possible photo- catalytic mechanism for the europium-doped graphitic carbon nitride was proposed.     

射频磁控溅镀掺杂铜对钛酸锌薄膜中相变化及微结构的影响

探讨了ZnTiO₃薄膜掺杂Cu元素对于薄膜性质、相变化与微结构之影响.实验是在一定温度下以射频磁控溅镀系统将铜沉积于ZnTiO₃陶瓷靶上,控制沉积于ZnTiO₃陶瓷靶上铜含量之后,再沉积掺杂铜的钛酸锌薄膜于SiO₂/Si基板上.成长出来的薄膜经由ESCA分析得知铜的质量分数分别为0.84%、2.33%和2.84%.从XRD分析常温下掺杂Cu的ZnTiO₃薄膜为非晶质态,经过600℃退火后,ZnTiO₃薄膜则由非晶质态转变成Zn₂Ti₃O₈结晶相,而未掺杂铜的ZnTiO₃薄膜在600℃退火时并没有结晶相产生.ZnTiO₃薄膜经过900℃退火后,Zn₂Ti₃O₈相分解成Zn₂TiO₄相和TiO₂相,且ZnTiO₃晶格常数因为Cu离子置换至Zn离子的位置有变小的趋势.由TEM分析证实Cu离子与Zn离子的置换,导致晶格应变产生双晶缺陷.经由XRD、SEM和TEM分析得知掺杂太多的铜会抑制TiO₂相的生成,而随着过多的Cu析出,晶体平均晶粒慢慢变小晶格应变也随之降低,以致晶格常数回复往原来晶格常数方向趋近.     

Controllable synthesis of argentum decorated CuOx@CeO2 catalyst and its highly efficient performance for soot oxidation

In this paper, CuO_x@Ag/CeO₂ catalysts were synthesized by simple wet-chemical method and equal volume impregnation method. The obtained catalysts were subjected to soot temperature programmed oxidation (soot-TPO) activity tests and were further characterized by various techniques such as X-ray diffraction (XRD), transmission electron microscopy/high-resolution transmission electron microscopy (TEM/HR-TEM), N₂ physisorption, X-ray photoelectron spectroscopy (XPS) and H₂-temperature programmed reduction (H₂-TPR). The results show that CuO_x@Ag/CeO₂ synthesized presents well controlled core-shell structures, with nano-cube like Cu₂O as the core and Ag decorated polycrystalline CeO₂ grafting layers as the shell. Such core-shell structured CuO_x@Ag/CeO₂ can successfully construct a secondary oxygen delivery channel (CuO_x → CeO₂ → Ag) to effectively transfer bulk oxygen of the catalyst to the soot, resulting in its excellent soot oxidation activity compared to CuO_x@CeO₂. The potential benefiting effect by Ag introduction over Cu@Ag/Ce can be concluded as: (i) pumping lattice oxygen and accelerating gaseous O₂ dissociation to generate significantly increased active surface oxygen content; (ii) modulating a moderate surface oxygen vacancies concentration to maintain more highly active O₂^– species.     

Friction, wear, and targeted synthesis of rubbing surfaces of self-lubricating composites

Self-lubricating copper-based composites are developed. It is shown that the structure of the surface layer, which is formed and deformed by the friction forces at the interface, is the major contributor to the friction process. The main stages of developing highly efficient tribotechnical materials for extreme operating conditions (high pressing forces and sliding velocities, absence of lubrication, high vacuum) are examined. A comprehensive approach to constructing tribotechnical composite systems is used to develop several copper-based materials for different operating conditions; in particular, self-lubricating antifriction composites to perform in high-speed friction pairs as well as in tribotechnical systems operating under high vacuum. __________ Translated from Poroshkovaya Metallurgiya, Vol. 46, No. 3–4 (454), pp. 11–19, 2007.     

Facile synthesis of nanoceria by a molten hydroxide method and its photocatalytic properties

Ceria nanoparticles were facilely synthesized by a molten NaOH-KOH hydroxide flux method with the precursor of Ce(NO_3)_3·6H_2O under different conditions in alumina crucibles or Teflon-lined stainless steel autoclave.The XRD patterns and TEM images show that both the crystal and particle sizes of synthesized nanoceria are around 10 nm.XPS results reveal that the nanoceria obtained in alumina crucible has a Ce~(3+) fraction of 17.1% which is higher than that of ceria synthesized in the Teflon vessel,the FTIR spectra of nanoceria prepared in alumina crucible show a stronger intensity of O-H stretching mode.UV-DRS and PL spectra results show that the nanoceria synthesized in alumina crucible with a calculated band gap of 2.9 eV has a wider responding light wavelength and a lower photogene rated electron-hole recombination rate,due to a higher concentration of oxygen vacancies(Ce~(3+)%).The photocatalytic results show that the degradation ratio and rate of the Rhodamine B(RhB) solution with the nanoceria synthesized in alumina crucible are 98.39% and 0.02919 min~(-1),both of which are larger than those of the ceria obtained from Teflon vessel.This method proves to be a simple and scalable way to synthesize nanoceria with rich oxygen vacancies and high photocatalytic activity.     

水热法合成Ag2C03／ZnO异质结复合光催化剂及其光催化性能

采用水热法合成了一系列不同Ag2CO3含量的新型Ag2CO/ZnO异质结复合光催化剂,运用X射线粉末衍射（XRD）、扫描电镜（SEM）、X射线光电子能谱（XPS）、傅里叶变换红外光谱（FT-IR）、紫外-可见漫反射吸收光谱（UV-visDRS）等系列手段对所制备的光催化剂进行了表征,并以紫外光（254nm）为光源,评价了催化剂光催化降解甲基橙的活性,考察了不同Ag2CO3复合量、不同水热温度对ZnO复合光催化剂反应活性的影响．结果表明．当Ag2CO3含量为2％、水热温度为140℃,复合光催化剂具有最大的光催化活性,降解率达到86．31％．Ag2CO3/ZnO异质结复合光催化剂具有更高的光催化活性主要原因是复合光催化剂对紫外光有很强的吸收能力,适量A龅C03能提高光生电子一空穴对的分离效率,并改善催化剂的物理性能．     

不同底层(Ag, Ti, Cu, Pt)对[Fe/Pt]n多层膜磁性的影响

利用磁控溅射的方法, 在热玻璃基片上制备了[Fe/Pt]n多层膜, 经不同温度真空热处理后, 得到L10有序结构的FePt薄膜(L10-FePt).实验结果表明 [Fe/Pt]n多层膜结构可使FePt薄膜的有序化温度由500 ℃降到350 ℃, 350 ℃退火20 min后其平行膜面矫顽力可达到421.8 kA·m-1.同时以Ag, Ti, Cu和Pt做底层, 利用[Fe/Pt]n多层膜结构制备了FePt薄膜, 磁性和X射线衍射结果表明 与[Fe/Pt]n多层膜相比, 四种底层均没有进一步降低FePt薄膜的有序化温度, 其中Ag做底层对[Fe/Pt]n多层膜退火后的平行膜面矫顽力影响较小, 但能够提高其垂直磁各向异性;其他底层均会降低[Fe/Pt]n多层膜在高温退火时的平行膜面矫顽力, 且对其垂直磁各向异性无改善作用.