溶剂热法制备不同微米结构的氧化亚铜

以乙酸铜为原料,采用溶剂热法合成了球形直径约为2~3μm和八面体粒径大小约为4μm的氧化亚铜颗粒。通过选用不同的还原剂如三乙醇胺和乙二醇,系统研究了不同反应体系中如反应温度、溶剂、原料配比和添加表面活性剂十六烷基三甲基溴化铵(CTAB)对微米结构氧化亚铜晶型与形貌的影响,选出制备氧化亚铜八面体和球形的最佳条件,并初步探讨了氧化亚铜微米颗粒的生长机理。     

层状硫化锌的溶剂热法制备

以乙酸锌Zn(CH3COO)2.2H2O为锌源、硫脲SC(NH2)2为硫源、水与乙二胺的混合溶液为反应溶剂、十二烷基磺酸钠C12H25SO3Na形成的胶束为模板,利用溶剂热法制备了具有层状微观形貌的ZnS粉体材料。利用XRD、SEM、EDS等测试手段进行表征,结果表明,所得ZnS粉体材料结晶良好,层状形貌明显;层状ZnS粉体材料在435nm附近有较宽的发射峰,且发光性能明显优于球状ZnS粉体材料。     

溶剂热法制备氧化锆纳米粉体及其发光性能

以乙醇为反应介质通过溶剂热法合成了氧化锆纳米粉体。采用X射线衍射（XRD）、透射电镜（TEM）及荧光光谱（PL）等测试技术对产物相组成、形貌结构及发光性能进行了表征。XRD结果表明,以KOH为沉淀剂制备的凝胶前躯体经140℃溶剂热反应3小时后所得的产物粉体由单一的四方相ZrO2组成,随着反应温度的升高单斜相ZrO2含量逐渐提高。TEM测试结果表明,不同温度合成的ZrO2纳米粉体形貌没有显著差异。产物粉体均为球形颗粒且可观察到较为明显的团聚现象。PL谱测试结果表明,140℃溶剂热合成的氧化锆粉体在250nm的紫外光激发下在402nm和625nm处分别有一个较强的宽发射峰和一个弱发射峰。     

溶剂热法制备YAG微粉及其机理分析

采用异丙醇溶剂为反应介质,通过溶剂热法低温合成了YAG粉体.利用XRD、TEM、IR对产物微观形态和晶体结构进行了表征.研究证明,在300℃下保温10h可以得到平均粒径为200nm的球形单分散YAG微粉,通过温度对反应进程的影响分析了YAG形成机理即溶解-结晶过程.     

水热/溶剂热法合成不同形貌结构光催化剂BiVO4的研究进展

BiVO4光催化剂的颗粒粒径、物相及形貌结构等因素都对其催化性能有显著影响,因此制备粒径、物相及形貌结构可控的BiVO4光催化剂具有重要意义。水热/溶剂热法是目前合成光催化剂BiVO4的一种重要方法,从影响水热/溶剂反应体系的因素方面概述了水热反应温度、反应时间、反应液pH值、表面活性剂以及反应溶剂等对终产物BiVO4的颗粒尺寸、物相结构以及形貌的影响。     

溶剂热法制备TiO_2-CuO复合颗粒及其光催化性能

采用溶剂热法制备TiO2-CuO复合颗粒,表征了复合颗粒的形貌、结构并研究其模拟太阳光下光催化还原CO2生成甲醇的性能,探讨了TiO2-CuO光催化还原CO2的机理。结果表明:TiO2-CuO复合颗粒为平均粒径约为4.5μm的空心球形颗粒,硫酸铜在复合颗粒的制备过程中具有模板剂和金属源的作用。CuO质量分数为8%的TiO2-CuO复合颗粒具有较高的光催化还原效率,在异丙醇作用下,甲醇产量达127.8μmol/g;CuO复合及异丙醇的添加能够促进电子和空穴的分离,提高光催化还原CO2效率。     

溶剂热法中Na_2S浓度对银纳米线合成的影响

系统地探讨了溶剂热法中不同Na2S浓度对制备银纳米线的影响。采用扫描电镜、X射线衍射仪和紫外-可见分光光度计对样品进行表征及分析。结果表明,Na2S浓度对银纳米线的合成有着重要的影响,在一定浓度范围内,随着Na2S浓度的增加,银纳米线逐渐增加;当Na2S浓度为1mmol/L时,可以得到尺度均匀的纯银纳米线,浓度过大时又会出现类球状银纳米颗粒。     

氮化铝的溶剂热合成及形貌研究

通过溶剂热方法合成出了氮化铝材料,并研究了溶剂种类、温度、表面活性剂等不同条件对合成氮化铝粉末的结晶度、纯度和形貌的影响。实验中通过控制条件得到了棒状、片状、球状和多孔形貌的氮化铝粉末。结果发现,用二甲苯为溶剂合成的氮化铝结晶度好,而生成的氮化铝纯度随着反应温度升高而增加,同时表面活性剂的加入对结晶度也存在一定的影响。     

四氧化三铁纳米晶的热溶剂法制备研究

采用切片石蜡作为热溶剂法的高温溶剂来制备四氧化三铁纳米晶,在300~340℃的石蜡溶剂中,研究了油酸铁直接热解制备四氧化三铁纳米晶过程中溶剂的温度和反应物连续注入的方式对纳米晶的粒度和形貌的影响规律。结果表明,采用反应物连续注入的方式可制备出单相、形貌规则、平均粒径在24~60 nm,标准偏差在11%~13%的Fe3O4纳米晶。热溶剂温度在一定范围内对纳米晶尺寸影响不大,纳米晶的平均尺寸随着反应物注入速度的提高而减小。     

水热／溶剂热法制备Mn3O4纳米材料的研究进展

Mn3O4广泛应用于催化、电化学、软磁材料、空气净化等领域。近年来，采用多种新技术研制Mn3O4新材料，如电子级Mn3O4、Mn3O4超细粉体、Mn3O4纳米带、纳米棒、纳米纤维、纳米空心球等。重点评述了近几年水热／溶剂热法制备纳米级Mn3O4新材料的研究进展，并展望了Mn3O4新材料制备技术的发展方向。     

Study on morphologies of Co microcrystals produced by solvothermal method with different solvents

Cobalt microcrystals with different sizes and morphologies were fabricated via a facile solvothermal method. The effects of different solvents on the sizes and morphologies are investigated separately. Flowerlike cobalt with around tens of microns in diameter is obtained in ethanol. Meanwhile, of microdisks and octadecahedra with the edge lengths about several microns are fabricated in ethylene glycol and glycerol, respectively. Reduction potential and viscosity rank of the solvents play the important roles in controlling the sizes and morphologies of cobalt. Moreover, room-temperature magnetic measurement shows that the magnetic properties of cobalt microcrystals depend on their morphologies.     

水热法制备不同形貌的氧化锌纳米结构

采用水热法,用甲酰胺水溶液和锌片建立反应体系,在不同种晶层上制备出不同形貌的ZnO纳米结构,所用基底有Si片、镀有ZnO薄膜的Si片、镀有ITO薄膜的Si片、涂有ZnO粉末的Si片等,研究了不同的种晶层对ZnO纳米结构的形貌的影响。在不同温度下,分别在镀有ZnO薄膜和ITO薄膜的医用载玻片衬底上生长ZnO纳米结构,研究了温度在水热法中的作用及种晶层对纳米杆长度的影响。实验中用扫描电子显微镜（SEM）和X射线衍射仪（XRD）对纳米聚集体进行了表征。SEM表征结果表明不同种晶层上获得的ZnO纳米结构形貌差异很大;反应时间、甲酰胺水溶液浓度以及反应温度对ZnO纳米阵列形貌都有着一定的影响;在ZnO薄膜上生长的纳米杆较在ITO薄膜上生长的纳米杆长。SEM图像同时表明氧化锌纳米杆随着温度的增大,纳米杆的长度和杆径增大。X射线衍射峰在34.6℃有很强的（002）纤锌矿衍射峰,该峰表明衬底上有高度c轴取向的大面积纳米杆阵列和较好的结晶质量。     

Tube- and ball-like amorphous MoS2 prepared by a solvothermal method

Amorphous MoS₂ was synthesized solvothermally in pyridine at 190 °C. XRD pattern indicated that the amorphous MoS₂ was made up of single layer and layer stacking had not taken place. TEM images showed that tube- and ball-like morphologies existed in the amorphous MoS₂. Electron diffraction did not reveal any crystal ordering in the tube and ball, which indicated that the tube and ball were completely amorphous. The influences of reaction conditions on the formation of these morphologies were also discussed. It was proposed that the formation of the tube- and ball-like structures might be energy-favorable for the single layer of MoS₂ under the synthesis conditions.     

YAG:Ce nano-sized phosphor particles prepared by a solvothermal method

Nano-sized Ce-doped YAG phosphor particles were synthesized by a mixed solvothermal method using the stoichiometric amounts of inorganic aluminum and yttrium salts. The formation of YAG:Ce was investigated by means of XRD and TG-DTA. The purified YAG crystalline phases was obtained under moderate synthesis condition (300 °C and 10 MPa), this indicated that ethanol replaced part of water as solvent favoring the formation of YAG. TEM images showed that YAG:Ce phosphor particles were basically spherical in shape, well dispersed and a mean grain size about 60 nm. The particle absorbed excitation energy in the range 403-510 nm, and the maximum excitation wavelength was near 470 nm. The crystalline YAG:Ce showed broad emission peaks in the range 480-650 nm and had maximum intensity at 528 nm. The excitation and emission intensity increased with increasing the synthesis temperature from 280 to 300 °C, and get the maximum brightness at 300 °C.     

Cupric oxide inclusions in cuprous oxide crystals grown by the floating zone method

Abstract

Phase-pure cuprous oxide (Cu₂O) crystals are difficult to grow since cupric oxide can form within the crystal as the crystal is cooled to ambient conditions. Vacancies are the solute which causes precipitation of macroscopic defects. Therefore, even when a mostly phase-pure single crystal is used as a feed rod, cupric oxide inclusions persist in the recrystallized solid. Control of the thermal profile during crystal growth, however, can improve phase-purity; a slow counter-rotation rate of the feed and seed rods results in fewer inclusions. Cupric oxide can be removed by annealing, which produces a factor of 540 ± 70 increase in phase-purity.     

Thin cuprous oxide films prepared by thermal oxidation of copper foils with water vapor

We present an improved preparation method for the growth of high quality crystals of cuprous oxide films grown by thermal oxidation of cupper foils with water vapor. This method proved to be good for preparing cuprous oxide films with high purity and large grain size. X-ray diffraction studies revealed the formation of Cu₂O films with preferred (111) orientation. The cuprous oxide diodes fabricated by the above technique have been studied using current-voltage method.     

The mechanical behaviour of cuprous oxide

The stress-strain behaviour under compresion at constant strain rate of single crystals (051 and 122) compression axis) and polycrystalline samples of cuprous oxide have been examined at room temperature and hydrostatic pressure up to 12 kb and at atmospheric pressure and high temperature up to 600° C. At high environmental pressure, plastic flow occurs at 6 kb. At high temperatures and one atmosphere, extensive plastic deformation was observed after 500° C. The resultant slip planes were of the {110} and {100} types. Transmission electron microscopy of thin foils prepared from deformed specimens shows that the Burgers' vectors of the glide dislocations are of the 111, 110 and 100 types.     

Effect of mixed solvent on the morphologies of nanostructured Bi2S3 prepared by solvothermal synthesis

Different morphologies of nanostructured bismuth sulfide (Bi₂S₃) including nanotubes and nanorods have been prepared by solvothermal synthesis at a low temperature of 120 °C for 12 h using various mixed solvents as the reaction medium and urea as the mineralizer. X-ray diffraction analysis showed that all the as-prepared Bi₂S₃ samples are orthorhombic phase. Transmission electron microscopy analysis showed that the morphologies of the nanostructures are mainly related to the viscosity and surface tension of the mixed solvent used in the solvothermal synthesis.     

微波水热法制备纳米ZnO粉体的研究

以硝酸锌和氢氧化钠为原料,通过微波水热法制备了ZnO纳米粉体。采用X射线衍射、透射电镜、激光粒度分析、比表面测试等手段对微波水热产物进行表征,并探讨了溶液体系pH值、反应温度、反应时间对微波水热反应所得ZnO粉体性能的影响。结果表明,微波水热反应体系的pH值、反应温度对所制备粉体的粒度分布有重要影响。制备ZnO纳米粉体的最佳反应条件为:溶液体系pH值为5,反应温度为130℃,反应时间为10min,在此工艺条件下制备的ZnO粉体比表面积为18.53m2/g,平均粒度约为61nm,粒径分布狭窄,结晶完整。