针状In_2O_3微纳材料的制备、表征及其光催化性能研究

在In(NO3)3、没食子酸、甲酰胺和水的反应体系中,通过简单的常压回流方法,制备了体心立方结构的In2O3微纳材料的前驱体。针状前躯体经800°C煅烧5 h后即转变为C-In2O3,粒子保持了良好的形貌继承性。样品通过透射电镜、X射线衍射、红外光谱和元素分析等手段进行了表征。研究发现,溶液中没食子酸、甲酰胺及In(NO3)3的浓度均对粒子的形貌及尺寸产生影响;采用甲基紫为模型反应评价了针状In2O3的光催化活性,结果表明,针状In2O3微纳材料对甲基紫的紫外光降解具有良好的催化作用。     

立方形貌ITO粉体的水热法制备及光电性能

以金属In和SnCl_4·5H_2O为原料,采用水热法在120~140℃得到In(OH)_3前驱体,该前驱体在550℃下煅烧得到立方体形貌的氧化铟锡粉体.研究了水热反应温度和反应时间对粉体形貌和晶型的影响.通过热分析仪(TG-DSC)、X射线衍射仪(XRD)、拉曼光谱仪(Raman)、透射电子显微镜(TEM)、四探针电阻仪、X射线光电子能谱仪(XPS)、紫外-可见-近红外分光光度计以及荧光光谱仪对粉体进行了表征,并对水热反应条件为140℃及12 h下制备的c-ITO的光电性能进行了分析.结果表明,随着水热反应温度的升高,ITO粉体形貌由立方体向不规则形貌转变,粉体晶型出现少量的六方相.在水热反应条件为140℃,12 h,铟离子与尿素的摩尔比为1∶5时,得到平均粒径为230 nm的立方体ITO粉体,其电阻率为1.247Ω·cm,光学能带间隙为3.685 e V,与c-In2O3相比其能带间隙更高,室温下260 nm激发波长下粉体出现光致发光,发射峰位于蓝光区域.     

纳米磷灰石晶体的制备

在人体骨中,不同的年龄段,不同部位的生物磷灰石晶体的尺寸和形貌有差异[1-3],人们已经制备出纳米级类骨磷灰石晶体模拟天然骨磷灰石。合成方法、条件、反应的前驱物等不一样,得到晶体的形貌、尺寸也不一样[3,4]。本文用硝酸钙的二甲基甲酰胺溶液和磷酸钠水熔液反应制备纳米磷灰石晶体并研究其形貌和尺寸。1　材料和方法30克分析纯硝酸钙在搅拌下加入45克分析纯二甲基甲酰胺中(A)。18克分析纯磷酸纳溶解于1500ml去离子水中(B)。B加热到25℃,不断搅拌下,缓缓将溶液A滴入其中,滴定完后继续搅拌2h,温度控制在70℃。室温陈化24h、离心分离…     

溶剂热法合成不同形貌的Co3O4及其电容特性

采用溶剂热法以不同的钴盐在水-正丁醇体系中合成了不同形貌及尺寸的纳米Co3O4. 采用XRD和TEM对产物的物相和形貌进行表征. 结果表明, 通过改变反应体系中阴离子的种类, 可以控制产物Co3O4的形貌与晶粒尺寸. 通过循环伏安法、恒流充放电和交流阻抗法对Co3O4电极材料的电化学性能进行表征. 结果表明, Co3O4的形貌与晶粒尺寸对其电化学性能有显著影响. 在2 mol·L-1 KOH溶液中, 在-0.40 - 0.55 V (vs SCE)电位范围内, 由Co(NO3)2制备的球形Co3O4表现出更好的电容特性,单电极初始比容量达362.0 F·g-1, 经过400 次循环后比容量仍保持90%.     

反应溶剂对Bi2S3粉体形貌的影响

利用溶剂热法在不同反应溶剂中制备了不同尺寸的Bi2S3纳米管和纳米棒.利用XRD、SEM、TEM、选区电子衍射(SAED)和高分辨透射电镜(HRTEM)对其结构和形貌进行了表征.结果表明,所制备的产物是结晶良好的正交相Bi2S3,反应溶剂的表面张力、粘度大小和反应溶剂中的比例影响纳米粉体的形貌和尺寸.紫外-可见光吸收光谱测量表明,由于尺寸效应所有粉体的吸收谱相对于正交相的Bi2S3块体都出现蓝移.     

水热对纳米Ni（OH）2电化学性能的影响

采用微乳法制备纳米Ni(OH)2,用X射线衍射、扫描电子显微镜、透射电子显微镜、恒流充放电、循环伏安、交流阻抗等测试技术研究了纳米Ni(OH)2的微观结构、表面形貌和电化学性能. 结果表明,140 ℃水热和微乳/水热2种方式处理得到的纳米Ni(OH)2具有不同形貌特征. 水热和微乳/水热处理虽然不影响纳米Ni(OH)2的活化性能,但对纳米Ni(OH)2的放电比容量影响很大,采用140 ℃水热和微乳/水热处理比单纯的微乳法制备得到的纳米Ni(OH)2的放电比容量分别提高了24.6和74.8 mA·h/g. 处理后的纳米Ni(OH)2的循环伏安峰电流增大、电荷转移电阻由2.633 Ω分别降至2.464和1.679 Ω.     

多元醇还原法制备片状六边形Fe3O4纳米颗粒

在表面活性剂油酸和油胺,液相环境二苄醚体系中,利用多元醇还原法,采用1,2-十二烷二醇还原前驱体乙酰丙酮铁Fe(acac)3,通过表面活性剂、金属前驱体以及液相环境的共同作用,制备出了单分散片状六边形Fe3O4纳米颗粒。分析了表面活性剂以及还原剂多元醇对纳米颗粒尺寸及形貌的影响。TEM表征结果显示：与未使用表面活性剂的情况相比,油酸和油胺的加入抑制了颗粒的生长,使颗粒尺寸从24.2 nm降低到10.7 nm;颗粒形貌多样化,出现了片状六边形形貌的Fe3O4纳米颗粒。磁性能检测表明： Fe3O4纳米颗粒具有高饱和磁化强度（Ms=88 emu/g）和零剩磁的特点,有望作为磁标记材料应用在生物检测上     

LiFePO4纳米晶的尺寸、形貌调控及锂电池性能研究

由于材料的电化学性能与其尺寸、形貌和结构密切相关,本文围绕乙二醇体系制备LiFePO_4纳米晶展开了材料的尺寸和形貌调控合成探索,并对材料进行了锂电池性能表征。改变体系的反应物浓度,LiFePO_4纳米晶的尺寸明显发生变化,当体系中FeSO_4的浓度为0.15mol/L时,得到的LiFePO_4纳米晶尺寸最小,其锂离子电池的容量稍高于其他尺寸的LiFePO_4纳米晶。葡萄糖的添加量对LiFePO_4纳米晶的形貌会产生影响,但对锂离子电池性能影响不大。     

多形貌Bi_2O_3微纳材料的制备及其光催化性能研究

本文在PEG4000(DL-天冬酸形成的复合软模板体系中,通过常压回流和改变碱源的方法成功合成出不同形貌的前驱体,经550℃煅烧3 h后得到γ-Bi_2O_3,且形貌保持良好的继承性。运用场发射扫描电子显微镜(FE-SEM)、X射线衍射(XRD)、紫外-可见吸收光谱(UV-Vis)、热重(差热扫描量热分析(TG(DSC)和紫外(可见漫反射光谱(UVDRS)等手段对样品进行了表征和分析。继而研究了不同形貌γ-Bi_2O_3微纳材料对有机染料甲基紫的光催化降解能力,在紫外光照射下,由纳米片状粒子组装形成的花状Bi_2O_3-1微纳材料能在40min内使甲基紫水溶液的脱色率达到99.68%,而微米级棒状Bi_2O_3-2也可在100 min后使甲基紫的脱色率达到99.85%。     

配位-均匀沉淀法合成Cd（OH）2和CdO纳米带

以硝酸镉为前驱物、氨水(25-28 wt%)为沉淀剂,在无模板的条件下,采用配位-均匀沉淀法成功地合成了Cd(OH)2纳米带。将Cd(OH)2纳米带在350℃下煅烧4 h得到形貌相似的CdO半导体纳米材料。X-射线衍射(XRD)、扫描电镜(SEM)、透射电镜(TEM)、电子衍射(SAED)等测试结果表明,所制备的Cd(OH)2纳米带是由尺寸约25 nm的Cd(OH)2纳米粒子组成,其宽度为100-200 nm、长度达1.5 um、厚度约为30 nm;Cd(OH)2为六方晶系结构;CdO纳米带由更小的CdO纳米粒子组成,CdO为面心立方晶型。本文还初步探讨了Cd(OH)2纳米带的形成过程。     

常压水热法合成玉米棒状In_2O_3及其性能研究

以In(NO_3)_3·4.5H_2O和(NH_2)_2CO为原料,采用常压水热法于95℃反应22 h制得氧化铟(In_2O_3)前驱物氢氧化铟,于600℃煅烧2 h合成了In_2O_3粉体,其结构、形貌及性能经紫外-可见(UV-Vis)光谱、X-射线衍射(XRD)、拉曼光谱和扫描电镜(SEM)表征。以甲基橙为目标降解物,研究了In_2O_3粉体的光催化活性。结果表明:In_2O_3粉体为体心立方晶系方铁锰矿结构和亚稳相刚玉六方结构的混合体,In_2O_3的UV-Vis谱图中出现了明显的蓝移。当In(NO_3)_3·4.5H_2O和(NH_2)_2CO物质的量比为1∶7时,In_2O_3粉体中出现了玉米棒状结构,棒状体长度约为500 nm,直径约150 nm;该棒状结构的In_2O_3对甲基橙有较好的光催化活性,在紫外光照射6.5 h后甲基橙的降解率为69.7%。     

Preparation of size‐controlled In2O3 nanoparticles

Highly crystalline and monodisperse In₂O₃ nanoparticles were successfully prepared by thermal decomposition of In(dipy)₃Cl₃·2H₂O in oleylamine and oleic acid under inert atmosphere. The size of In₂O₃ nanoparticles could be readily tuned from 10–15 nm to 40–50 nm, depending on the molar ratio of precursor to combined solvent in the reaction system. As‐synthesized In₂O₃ nanoparticles have a center‐body cubic structure as characterized by powder X‐ray diffraction and selected‐area electron diffraction. Transmission electron microscopy images showed that In₂O₃ nanoparticles have a narrow size distribution. A relatively strongly PL peak centered at 378 nm could be clearly seen when 10–15 nm In₂O₃ nanoparticles redispersed in cyclohexane were excited at 275 nm at room temperature. Copyright © 2007 John Wiley & Sons, Ltd.     

Structural investigations and luminescence of In2Ge2O7 and In2Si2O7

The crystal structures of the ordinary pressure forms of indium digermanate In₂Ge₂O₇ and disilicate In₂Si₂O₇ have been studied from X-ray powder diffraction data by Rietveld refinement. They are closely related to that of the thortveitite which crystallizes in the monoclinic system with the space group C2/m and Z = 2. They show luminescence properties below 160 K and 200 K respectively. The luminescence is discussed in terms of crystal structure and compared to that of some other luminescent indium oxides.     

Z-Scheme In2S3/NU-1000 Heterojunction for Boosting Photo-Oxidation of Sulfide into Sulfoxide under Ambient Conditions

Photocatalytic oxidation of sulfide into sulfoxide has attracted extensive attention as an environmentally friendly strategy for chemical transformations or toxic chemicals degradation. Herein, we construct a series of In₂S₃/NU-1000 heterojunction photocatalysts, which can efficiently catalyze the oxidation of sulfides to form sulfoxides as the sole product under LED lamp (full-spectrum) illumination in air at room temperature. Especially, the sulfur mustard simulant, 2-chloroethyl ethyl sulfide (CEES), can also be photocatalytically oxidized with In₂S₃/NU-1000 to afford nontoxic 2-chloroethyl ethyl sulfoxide (CEESO) selectively and effectively. In contrast, individual NU-1000 and In₂S₃ show very low catalytic activity on this reaction. The significantly improved photocatalytic activity is ascribed to the constructing of an efficient Z-scheme photocatalysts In₂S₃/NU-1000, which exhibits the enhancement of light harvesting, the promotion of photogenerated electron-hole separation, and the retention of high porosity of the parent MOF. Moreover, mechanism studies in photocatalytic oxidation reveal that the superoxide radical (^.O₂⁻) and singlet oxygen (¹O₂) are the main oxidative species in the oxidation system. This work exploits the opportunities for the construction of porous Z-scheme photocatalysts based on the photoactive MOFs materials and inorganic semiconductors for promoting catalytic organic transformations. More importantly, it provides a route to the rational design of efficient photocatalysts for the detoxification of mustard gas.     

Cr对In/WO3/ZrO2催化剂上甲烷选择性催化还原NO的促进作用

分别采用浸渍法和机械混合法制备了Cr改性的In/WO3/zrO2(In/WZr)催化剂,考察了改性前后催化剂的CH4选择性催化还原NO的活性.结果表明,将Cr2O3与In/WZr机械混合可显著提高In/WZr催化剂活性,Cr的加入促进了气相中NO向NO2的转化.而浸渍法制备的Cr/InAVZr催化剂活性远低于改性前的In/WZr催化剂,这是由于在制备过程中部分Cr2O3转化为CrO3,使其氧化性大大提高,从而将CH4完全氧化为CO2和H2O,不利于将CH4活化为反应所需的中间活性物种.     

Coupled In/Te and Ni/vacancy ordering and the modulated crystal structure of a B8 type, Ni3±xIn1−yTe2+y solid solution phase

The commensurate superstructures of a NiAs/Ni₂In type parent structure, Ni_3.32InTe₂ and Ni_3.12In_0.86Te_2.14 (q=γ[0 0 1]^*, γ=2/3) as well as one dimensionally incommensurate structure of Ni₃InTe₂ (γ=0.71) were refined from neutron powder diffraction data (R_wp=4.77%, 4.53% and 4.91% for the three structures, respectively, at 298 K). The commensurate structures were refined in the P6₃/mmc space group (c=3c_NiAs). The stacking sequence at the hcp array is -In/Te/Te/- and the trigonal bipyramidal site within the In layer, Ni(2), is partially occupied while it is empty in the Te layers. The octahedral position in between the In and Te layers, Ni(1a), is fully occupied while the octahedral position in between two adjacent Te layers, Ni(1b), is partially occupied. With decreasing In and Ni content, the modulation wave vector, γ, was found to increase continuously until γ=1. From this, crenel functions to describe the whole homogeneity range of the solid solution were constructed with the length of the atomic domains Δ^Te=γ (and hence Δ^In=Δ^Ni=1−γ) and Δ^Ni(1b)=γ/2 (and hence Δ^Ni(1a)=1−γ/2) which were then used for the refinement of the incommensurate structure of Ni₃InTe₂. The corresponding effect in real space is that the single In layers separating double layers of Te occur less frequent when γ in increasing until at γ=1 the CdI₂ type structure of Ni_1+xTe₂ is reached.