Cu/TiO2 纳米线的制备及其光催化性能

以P25粉体为原料,采用水热法合成了TiO2 纳米线,通过NaBH4还原CuCl2溶液,在TiO2纳米线的表面负载了Cu纳米颗粒.利用透射电镜(TEM)、X射线光电子能谱(XPS)和紫外-可见光谱(UV-Vis)对产物进行了表征.结果表明,Cu纳米粒子均匀分散在纳米线表面,并且该Cu/TiO2纳米线在可见光区域表现出较强的吸收性能.光催化降解酸性红3R染料溶液测试表明,在TiO2纳米线表面负载Cu纳米颗粒对提高其催化性能具有积极作用.     

水热-溶剂热法制备纳米CdS

硫化镉（CdS）是典型的半导体材料之一，因其在光电、光学和催化方面的应用前景，引起了广泛的重视．文中结合水热法和溶剂热法，在高压釜中形成以水和正已烷为溶剂的两相溶剂，并借助超声分散，以氯化镉（CdCl2）和硫代乙酰胺（TAA）为原料，在不同的加热时间和加热温度条件下成功制得CdS纳米粒子和纳米棒，并用X射线衍射（XRD）、高分辨透射电镜（HRTEM）、扫描电镜（SEM）、能谱及荧光光谱（LS）对其晶型、形貌、尺寸、组成进行了袁征，结果表明，制得的CdS纳米粒子与纳米棒尺寸分布均匀，分散性好；加热时间和加热温度是CdS晶型的主要影响因素，即较低的温度有利于CdS立方晶的形成，较高的温度有利于六方晶的形成；同时，延长加热时间有利于晶型的完善，但颗粒粒径会随之增大．     

聚(N-苯基马来酰亚胺)-b-聚(4-乙烯基吡啶)-CdS纳米复合物的光学性质

用可逆加成锻炼链转移(RAFT)聚合方法合成了两亲性聚(N-苯基马来酰亚胺)-b-聚(4-乙烯基吡啶)-Cd2(PNPV-Cd2)高分子配合物.Cd2离子与4VP基团配位并与硫代乙酰胺分解产生的S2-离子原位生成CdS纳米粒子.聚(N-苯基马来酰亚胺)-b-聚(4-乙烯基吡啶)- CdS( PNPVCdS)中CdS的含...     

载银TiO_2纳米线的制备及其光吸收性能

以纳米TiO2(P25)粉体为原料,采用水热法合成了TiO2纳米线,通过葡萄糖还原Ag(NH3)2+,得到了表面载银(Ag)的TiO2纳米线。利用透射电镜(TEM)、X射线光电子能谱(XPS)和紫外-可见光谱(UV-Vis)对产物进行了表征。结果表明,Ag纳米粒子均匀分散在纳米线表面,并且该Ag/TiO2纳米线在可见光区域表现出较强的吸收性能。     

TiO2纳米管与纳米线的光电化学研究

利用在钛箔表面沉积一层TiO2纳米粒子作为晶种,与NaOH反应,通过改变反应温度制备了TiO2纳米管与纳米线.制备了TiO2纳米管和纳米线膜电极,并进行了光电化学测试.光电化学实验表明,混晶结构TiO2纳米管和纳米线显示出优良的光电转化性能.     

Ag纳米粒子修饰ZnO纳米线特性研究

利用水溶液法制备ZnO纳米线,使用真空热蒸发方法用Ag对ZnO纳米线进行表面修饰。用场发射扫描电子显微镜(FESEM)、X射线衍射(XRD)仪、吸收谱仪分析它们的表面形貌、物相结构及光学性质,同时分析了其场发射性能。结果表明,随着Ag修饰量的增加,ZnO纳米线表面上的Ag纳米粒子分布会由稀疏逐步到致密,最后Ag的纳米粒子几乎连在一起。测量吸收谱线发现修饰后的ZnO纳米线的吸收能力变强,但存在一个临界值,当修饰量超过临界值后,ZnO纳米线的光吸收能力会减弱。对修饰后ZnO纳米线的场发射性能进行初步测试,结果表明适当量的Ag修饰可以有效降低ZnO纳米线的场发射开启电压。     

纳米晶复合有序多孔材料的研究进展

有序多孔材料具有大小均匀、排列有序的孔道,并且其孔径在一定范围内连续可调,因此以有序多孔材料为模板,合成均匀负载的纳米粒子和有序阵列的纳米线得到广泛研究.综述了以氧化铝、氧化硅、氧化钛有序多孔材料为模板,合成纳米颗粒和纳米线阵列的方法.     

半导体纳米粒子的表面修饰及其光学性质研究

对半导体纳米粒子的表面修饰不仅可以获得稳定和具有良好分散性的体系,而且可以通过表面修饰分子与粒子表面的相互作用来控制其线性和非线性光学过程。利用胶体法和微乳液法合成CdS纳米粒子的水溶胶和有机溶胶,通过控制粒子表面富Cd~(2+),从而实现与有机配体的复合。系统研究了吡啶、2,2’-联吡啶、1.10-邻菲咯啉等有机配体对CdS水溶胶合成的影响,包括稳定性、尺寸控制、粒径分布等方面的探讨。用微乳液法合成了表面包覆表面活性剂的CdS纳米粒子有机溶胶,通过表面替换反应成功实现了用吡啶、2,2’-联吡啶对CdS纳米粒子的表面修饰,获得了一种表面包覆电中性配体同时带有表面活性剂阴离子作为平衡电荷的复合粒子体系;进而成功实现了用阴离子BPh_4~-对表面活性剂阴离子的替换,得到了一种类强电解质结构的纳米粒子。 研究了用微乳液法合成的、表面分别包覆表面活性剂、吡啶、2,2’-联吡啶的CdS纳米粒子的荧光性质和光解行为,发现含N杂环类分子能够强烈地猝灭CdS纳米粒子的荧光,并且用电荷转移猝灭机制成功地进行了解释。重点研究了表面修饰对纳米粒子二阶、三阶光学非线性的影响。二阶、三阶极化率的测量分别在超瑞利散射装置、简并四波混频装置上进行。纳米粒子二阶非线性的研究,属刚刚开始的阶段,其具体的     

应用DNA模版自组装CdS纳米线

近年来,由于具有双螺旋补偿结构,DNA分子作为智能模版被广泛应用于设计棒状或管状类的纳米结构.本文报道了应用DNA双螺旋模版将CdS纳米粒子自组装为CdS纳米线.制备的CdS纳米线由几根纳米线紧密缠绕在一起,也呈螺旋形结构,该结构在无机材料中是很少见的.该结构形成的主要原因归功于CdS纳米粒子和DNA分子间的强烈静电互作用,由于含自由基的CdS纳米粒子带负电荷,而氨基的DNA核酸根带正电荷.研究结果表明应用DNA模版制备纳米线是一种简便、高效的技术和方法.同时,DNA模版法也为从底上制备纳米级的材料和物体提供了广阔的空间.     

用SPM纳米刻蚀方法在Ti表面制备纳米结构的研究

本文用导电原子力显微镜 (AFM)针尖诱导局域氧化反应的方法 ,在Ti膜表面制备了TiO2 纳米结构。实验结果表明 ,Ti膜的氧化阈值为 - 7伏 ,制备的TiO2 纳米线的最小线宽达到 10nm ,TiO2 纳米线的高度和宽度随针尖偏压的增大而增大。在优化的氧化刻蚀条件下 ,通过控制针尖偏压和扫描方式制备出了图形化的TiO2 结构 ,本研究表明基于导电AFM的纳米刻蚀技术将成为构筑纳米电子器件的重要工具     

TiO2纳米颗粒/纳米线复合光阳极的染料敏化太阳能电池

首先采用水热合成技术制备TiO2纳米线粉末,然后采用溶胶-凝胶技术制备钛酸丁酯溶胶,向溶胶中加入适量的TiO2纳米线制备凝胶浆体,采用浸渍提拉法在透明导电玻璃上制备TiO2纳米颗粒/TiO2纳米线复合薄膜的光阳极.通过XRD、SEM,电池的I-V特性和电化学阻抗谱测试,研究TiO2纳米线的添加量对光阳极的结构、形貌和电...     

Preparation of CdS and ZnS nanoparticles using microwave irradiation

Nanoparticles of CdS, ZnS have been prepared by a very simple fast reaction between CdCl₂ or Zn(Ac)₂ and thioacetamide in aqueous solution using microwave irradiation. The nanoparticles were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), reflectance and photoluminescence spectra. The sizes of the sample as prepared were calculated by Debye–Scherrer formula according to XRD spectra to be about 9 and 3 nm for CdS and ZnS, respectively. Similar results can also been obtained in the TEM images.     

Controlling the synthetic pathways of TiO2-derived nanostructured materials

A comprehensive study of the hydrothermal synthesis of TiO2-derived nanostructured materials, including layered protonic trititanate (H2Ti3O7), metal-ion exchangeable titanate (Na(x)H(2-x)Ti3O7), TiO2(B) and anatase nanotubes and TiO2-anatase nanowires, was conducted. Nanoscaled tubular structures were found to be already present in the samples derived from prolonged hydrothermal process of bulk anatase TiO2 and could be converted to various types of nanotubes, nanowires or nanorodes by post-synthesis treatments. 0.1 M HCI acid wash and air annealing were the two key parameters to select the types of nanotubes/nanowires as the final products. XRD, Raman, TG, and XPS core level and valence band studies were carried out to elucidate our proposed synthetic pathways.     

掺铁二氧化钛纳米线的合成及其光催化性能

首次以钛酸丁酯、异丙醇等有机物为原料,在10M NaOH溶液中水解后,于180℃水热24h,一步法合成二氧化钛纳米线(TNWs),并用扫描电子显微镜(SEM)和X射线衍射(XRD)等手段表征其形貌和结构。结果表明,所得TNWs焙烧到950℃时,仍为锐钛矿相,表明本制备方法迟滞了二氧化钛由锐钛矿相到金红石相的转变。此外,以甲基橙为目标降解物,在300 W汞灯照射下,研究了不同水热温度、保温时间及掺杂量对掺铁二氧化钛纳米线(Fe-TNWs)光催化性能的影响。结果表明,于750℃焙烧4h制备的掺铁摩尔百分数为0.5%的TNWs,具有最强的光催化降解性能,其降解速率和效率较未掺杂的样品都有了大幅度的提高。     

TiO_2纳米带在强碱条件下的水热反应

研究了在不同浓度NaOH溶液中,于不同反应时间和温度的水热条件下,TiO2纳米带发生反应,进一步生成产物的结构和形貌。通过对产物的XRD和SEM的测试结果表明,在强碱条件下水热处理TiO2纳米带很容易生成具有层状结构的钛酸盐纳米带,NaOH溶液的浓度、水热反应时间和温度对产物的形貌影响不大。     

CdS and CdTeS quantum dot decorated TiO2 nanowires. Synthesis and photoefficiency

An easy process was developed to synthesize TiO(2) nanowires sensitized with CdS and CdTeS quantum dots (QDs) requiring no pretreatment of the TiO(2) nanowires prior to nanoparticle generation. CdS and CdTeS nanoparticles were firstly grown by an in situ colloidal method directly onto the TiO(2) surface, hence not requiring subsequent functionalization of the QDs. The resulting nanostructure assembly and composition was confirmed by transmission electron microscopy (TEM), x-ray photoelectron spectroscopy (XPS) and Raman spectroscopy. Successful decoration of the TiO(2) nanowires by the QDs was observed by TEM, while XPS spectra provided clear evidence for the coexistence of CdS and CdTeS QDs and TiO(2) nanowires. The electronic structure of the TiO(2) nanowires was preserved as indicated by Raman spectroscopy. Preliminary photocurrent measurements showed that inclusion of Te in CdS QDs improved the photocurrent efficiency. Compared to bare TiO(2) nanowires, CdS/TiO(2) nanoassemblies showed an enhancement in photocurrent efficiency of 300% while CdTeS/TiO(2) presented an improvement of 350%. This study indicates that the generation of strongly anchored CdS and CdTeS QDs on a TiO(2) nanowire surface is achievable without introduction of a linker molecule, whose presence is known to decrease the electron injection efficiency.     

Dissolution/recrystallization growth of titanate nanostructures by amorphous precursor

Understanding of growth mechanism is of technical importance for tailoring the size and morphology of titanate nanostructures. However, the growth mechanism of titanate nanostructures in alkali solution systems by using crystalline TiO₂ remains debating currently. In the present work, the amorphous precursor of titanium hydroxide precipitates, a highly disordered raw material, was used as the precursor to prepare the titanate nanostructures under hydrothermal conditions. SEM and TEM results show that the morphology of the titanate nanostructures developed from nanoparticles to nanosheets and then the titanate nanowires with an interlayer spacing of 0.786 nm as the reaction time prolonged. XRD and Raman spectra results display that layered titanate nanostructure were formed. These phenomena are similar to that of the titanate nanostructures prepared by the TiO₂ crystal in alkali solution systems. The findings provide direct evidence to strongly support that titanate nanostructures grow from dissolution/recrystallization process under hydrothermal process, allowing mediating the size and morphology of titanate nanostructures. Moreover, SEM and photocatalytic results implied that the washing process improved the photocatalytic activities, which had no effect on the overall morphology.     

钛酸盐中钠离子含量对其水热转化制备TiO_2纳米材料的影响

采用水热法制备了单晶TiO2纳米材料。用X射线衍射仪和透射电子显微镜对产物的晶相组成和形貌进行了表征。考查了钛酸盐中钠离子含量对其水热转化所得TiO2产物的相组成、形貌和尺寸的影响。当pH值为1,含有钠离子时,得到的是以菱形为主的直径为10nm左右的单晶锐钛矿纳米颗粒,不含钠离子时,得到的产物以单晶锐钛矿纳米颗粒为主,同时含有少量单晶金红石纳米棒。当pH值为4,含有钠离子时,得到的是具有高长径比的单晶锐钛矿纳米棒,宽为60nm左右,长为300～500nm左右,不含钠离子时,得到的是尺寸为20nm×60nm的短纳米棒。同时,探讨了钛酸盐中钠离子的影响机理。     

General synthesis of manganese-doped II-VI and III-V semiconductor nanowires

A general approach for the synthesis of manganese-doped II-VI and III-V nanowires based on metal nanocluster-catalyzed chemical vapor deposition has been developed. High-resolution transmission electron microscopy and energy-dispersive X-ray spectroscopy studies of Mn-doped CdS, ZnS, and GaN nanowires demonstrate that the nanowires are single-crystal structures and homogeneously doped with controllable concentrations of manganese ions. Photoluminescence measurements of individual Mn-doped CdS and ZnS nanowires show characteristic pseudo-tetrahedral Mn2+ ((4)T1-->(6)A1) transitions that match the corresponding transitions in bulk single-crystal materials well. Photoluminescence studies of Mn-doped GaN nanowires suggest that manganese is incorporated as a neutral (Mn3+) dopant that partially quenches the GaN band-edge emission. The general and controlled synthesis of nanowires doped with magnetic metal ions opens up opportunities for fundamental physical studies and could lead to the development of nanoscale spintronic devices.     

Synthesis of CdS nanoparticles based on DNA network templates

CdS nanoparticles have been successfully synthesized by using DNA networks as templates. The synthesis was carried out by first dropping a mixture of cadmium acetate and DNA on a mica surface for the formation of the DNA network template and then transferring the sample into a heated thiourea solution. The Cd(2+) reacted with thiourea at high temperature and formed CdS nanoparticles on the DNA network template. UV-vis spectroscopy, photoluminescence, x-ray diffraction and atomic force microscopy (AFM) were used to characterize the CdS nanoparticles in detail. AFM results showed that the resulted CdS nanoparticles were directly aligned on the DNA network templates and that the synthesis and assembly of CdS nanoparticles was realized in one step. CdS nanoparticles fabricated with this method were smaller than those directly synthesized in a thiourea solution and were uniformly aligned on the DNA networks. By adjusting the density of the DNA networks and the concentration of Cd(2+), the size and density of the CdS nanoparticles could be effectively controlled and CdS nanoparticles could grow along the DNA chains into nanowires. The possible growth mechanism has also been discussed in detail.