Trition X-100/C_(10)H_(21)OH/H_2O体系层状液晶中纳米羟基磷灰石粉体的合成

本文以Triton X-100/C10H21OH/H2O体系层状溶致液晶为模板,Ca(NO3)2和(NH4)2HPO4为反应物,在一定的pH条件下,通过三元相图确定了层状液晶单相区域,并合成了羟基磷灰石(HA)纳米颗粒。用傅立叶红外光谱(FTIR),X射线衍射(XRD)和透射电子显微镜(TEM)对产物进行了表征。并考察了不同助表面活性剂浓度和不同表面活性剂浓度对产物的形貌和尺寸的影响。结果表明所制备的HA纳米颗粒平均直径为8~10nm、长度在100nm左右,呈针状。助表面活性剂浓度对HA形貌及尺寸影响不大,但是在一定范围内改变表面活性剂浓度可以起到调控HA纳米颗粒形貌和尺寸的作用。     

一种新的离子液体表面活性剂软模板法合成碳酸锶纳米棒

在室温下,以SrCl2·6H2O和(NH4)2Co3为原料,采用咪唑季铵盐离子液体表面活性剂1-十六烷基-3-甲基咪唑溴盐[C16 mim]Br软模板法制备了SrCO3纳米棒.利用透射电子显微镜(TEM)对产物进行了表征.初步探讨了SrCO3纳米棒的形成机理.结果表明SrCO3纳米棒长度在200nm左右,由平均直径为1...     

室温固相化学反应法合成Cd(OH)2纳米棒

在表面活性剂聚乙二醇(PEG)存在下,利用Cd(Ac)2·2H2O,CdCl2·2.5H2O,3CdSO4·8H2O和CdCO3分别与NaOH在室温下进行固相化学反应,合成了一系列的Cd(OH)2纳米棒,并利用XRD,TEM和SEM对其结构和形貌进行了表征.实验结果表明,表面活性剂PEG在Cd(OH)2纳米棒的形成过程中充当软模板,对产物形貌的控制起到决定作用.利用这种表面活性剂辅助的软模板固相化学反应法合成一维纳米材料,具有简便易行、反应条件温和以及能耗低等优点.     

特殊形貌GdF3:Eu3+纳米发光材料的制备及性能

以PEG-2000、柠檬酸和甘氨酸为表面活性剂,采用水热法制备出扁平纳米棒、纳米花和纳米片状的GdF3:Eu3+发光材料,并对其结构和性能进行了表征.XRD结果表明,所得样品均为正交晶系.FESEM照片表明,使用不同表面活性剂所制备的产物形貌不同.研究了以PEG-2000为表面活性剂时反应物浓度对产物形貌的影响,并对其...     

孔壁含有沸石次级结构单元的MCM-48的合成及催化研究

以双表面活性剂（双极性头表面活性剂和三乙醇胺）为模板，以含有沸石次级结构单元的溶胶为前驱体，在碱性条件下合成了新型介孔分子筛MCM 48。研究了沸石前驱体和三乙醇胺对产物MCM 48形成的影响，XRD和TEM表征结果表明，样品具有较高的结晶度和规则的孔径；FTIR和N2吸附表征结果表明，产物MCM 48的孔壁中含有沸石的次级结构单元，从而使得样品具有更大的比表面积。产物的重芳烃轻质化反应催化活性表明，实验样品对重芳烃的转化率比常规的MCM 48高，转化率约高出11%，进一步证明了实验样品的孔壁中含有沸石的结构单元。     

六方相W03纳米带的制备与表征

以Na2WO4、K2SO4和H2C2O4为原料,采用两步水热合成法制备了六方相W03纳米带。首先,在探索pH值、K2SO4加入量、反应温度和时间以及表面活性剂等因素对WO3纳米带的前驱物钨酸盐形貌的影响后,给出了前驱物钨酸盐纳米带的合成条件,并讨论了纳米带的形成机理;然后,在180℃的水热条件下对前驱物再处理48h获得六方相WO3纳米带。测试结果表明,WO3纳米带的形貌保持较好,宽度在100—300nm间,长度可达数微米,沿纳米带长轴方向为[001]方向。     

草酸钴纳米棒的一步固相化学合成及其表征

在非离子表面活性剂聚乙二醇(PEG)存在的条件下, 利用不同的钴盐分别与草酸进行低热固相化学反应, 一步合成了一系列金属配合物草酸钴纳米棒, 并采用XRD, TEM, SEM等分析手段对其结构和形貌进行了表征. 实验结果表明: 在合适的表面活性剂存在下, 利用钴盐与草酸的固相反应一步即可得到一维草酸钴纳米棒, 钴盐的不同及表面活性剂聚合度的不同均会影响纳米棒的形貌. 表面活性剂PEG在草酸钴纳米棒的形成过程中起到类似软模板的作用, 并诱导产物纳米晶沿某一方向定向生长从而生成纳米棒.     

六方相WO3纳米带的制备与表征

以Na2WO4、K2SO4和H2C2O4为原料,采用两步水热合成法制备了六方相WO3纳米带.首先,在探索pH值、K2SO4加入量、反应温度和时间以及表面活性剂等因素对WO3纳米带的前驱物钨酸盐形貌的影响后,给出了前驱物钨酸盐纳米带的合成条件,并讨论了纳米带的形成机理;然后,在180℃的水热条件下对前驱物再处理48 h获得六方相WO3纳米带.测试结果表明,WO3纳米带的形貌保持较好,宽度在100～300 nm间,长度可达数微米,沿纳米带长轴方向为[001]方向.     

PbSe纳米棒的模板合成及其性质

在表面活性剂十六烷基三甲基溴化铵(CTAB)存在下,利用N2 H4·H2O还原H2SeO3合成出单质硒纳米管,然后以硒纳米管为模板,与Pb(NO3):和N2 H4·H2O在常压低温下反应,制备了PKSe纳米棒.采用电子透射电镜、X射线衍射等方法对产物进行了表征.探讨了PbSe纳米棒的形成机理和制备反应的影响因素.测定了产物的荧光性质,并利用电位扫描伏安法研究了所得PbSe纳米棒的电化学性质.结果表明,所得产物在碱性介质中电化学活性较高,在循环伏安曲线上出现明显的氧化峰和还原峰.     

SnS_2纳米材料的水热合成及光催化性质(英文)

在不同的表面活性剂和硫源的条件下,采用水热法制备了多种形貌的SnS2纳米材料,详细讨论了反应条件对其形貌和性质的影响,并采用X射线衍射(XRD)、扫描电镜(SEM)、和BET比表面积法对制备的样品的物相、形貌和组成进行了表征,通过光催化降解罗丹明B研究了所得样品的光催化性能。结果表明:表面活性剂和硫源对产物的结构和形貌起到了重要的作用。当Sn4+与表面活性剂的物质量的比为1∶1时,样品均为纯的六方相SnS2。采用柠檬酸三钠为表面活性剂、硫脲为硫源时制得的SnS2纳米片具有最大的比表面积,同时表现出了最优的光催化性能。     

一维亚微米多钼酸盐形貌可控合成及氧的电催化还原研究

通过调节反应pH值和反应物种实现了一维亚微米多钼酸盐的控制合成,以钼酸铵和十二烷基苯磺酸钠为原料,在pH=6时制备出亚微米线,在pH=2时制备出亚微米棒,而以钼酸铵和氯化钠为原料,在pH=6时制备出纳米带.在pH=6时,纳米材料在长胶束内生长成亚微米线,而pH值降低至2时,过多的H＋不仅会形成大量的Mo3O102-,还会使得胶束变短,因此使得亚微米材料变短,成为亚微米棒.在没有模板剂十二烷基苯磺酸钠时,多钼酸铵就会长成结构更为稳定的纳米带.循环伏安测试结果表明在有机溶剂中,多钼酸盐的亚微米棒对氧电催化还原具有优异活性.研究表明,由于有机醇能与电解质溶液中的H＋反应,因此有机醇能显著促进一维多钼酸盐亚微米材料的氧的电催化活性.     

Salt-induced vesicle formation from single anionic surfactant SDBS and its mixture with LSB in aqueous solution

Vesicles can be formed spontaneously in aqueous solution of a single anionic surfactant sodium dodecyl benzenesulfonate (SDBS) just under the inducement of salt, which makes the formation of vesicle much easier and simpler. The existence of vesicles was demonstrated by TEM image using the negative-staining method. The mechanism of the formation may be attributed to the compression of salt on the electric bilayer of the surfactant headgroups, which alters the packing parameter of the surfactant. The addition of the zwitterionic surfactant lauryl sulfonate betaine (LSB) makes the vesicles more stable, expands the range of formation and vesicle size, and reduces the polydispersity of the vesicles. The vesicle region was presented in a pseudoternary diagram of SDBS/LSB/brine. The variations of vesicle size with the salinity and mixing ratios, as well as the surfactant concentration, were determined using the dynamic light scattering method. It is found that the vesicle size is independent of the surfactant concentration but subject to the salinity and the mixing ratio of the two surfactants.     

The Effect of Sodium Dodecylbenzenesulfonate (SDBS) Micelles on a BelousovZhabotinsky Oscillating System Catalyzed with a Tetraazamacrocyclic Copper(II) Complex

This article deals with the influence of micelles of the anionic surfactant sodium dodecyl benzene sulfonate (SDBS) on the Belousov? Zhabotinsky (B? Z) oscillating reaction catalyzed by a tetraazamacrocyclic copper(II) complex [CuL](ClO₄)₂, an enzyme‐like catalyst (L=5,7,7,12,14,14‐hexamethyl‐1,4,8,11‐tetraazacyclotetradeca‐4,11‐diene). Unlike the classical B? Z oscillator in which malonic acid is usually used as a substrate, malic acid (an intermediate in the Krebs cycle) is involved in this oscillating system. Experiments reveal that formation of the SDBS micelles markedly affects the behavior of the oscillating reaction. It is found that there is a linear relationship between the change in the oscillation amplitude (ΔA) and the concentration of SDBS, whereas the change in the oscillation period (ΔT) is linearly proportional to the SDBS concentration. The most likely mechanism that involves the formation of the SDBS micelles and the effects of the micelles on the oscillating chemical system can be rationalized by assuming that the SDBS micelles are so negatively charged that they attract more [CuL]³⁺ than [CuL]²⁺. This hypothesis was confirmed by UV/VIS spectrophotometric measurements of a constant concentration of [CuL](ClO₄)₂ in different concentrations of SDBS; as the SDBS concentration increased, the absorbance of [CuL](ClO₄)₂ increased, while the maximum absorption wavelength for [CuL](ClO₄)₂ remained at 502 nm.     

Vesicles Formation Induced by Layered Double Hydroxides in Mixture of Lauryl Sulfonate Betaine and Sodium Dodecyl Benzenesulfonate

This paper reports that structurally positively charged layered double hydroxides (LDHs) nanoparticles induce the vesicle formation in a mixture of a zwitterionic surfactant, lauryl sulfonate betaine (LSB), and an anionic surfactant, sodium dodecyl benzenesulfonate (SDBS). The existence of vesicles was demonstrated by negative‐staining (NS‐TEM) and freeze‐fracture (FF‐TEM) transmission electron microscopy and confocal laser scanning microscopy (CLSM). The size of vesicles increased with the increase of volume ratio (Q) of Mg₃Al‐LDHs sol to the SDBS/LSB solution. A new composite of LDHs nanoparticles encapsulated in vesicles was formed. A possible mechanism of LDHs‐induced vesicle formation was suggested. The positive charged LDHs surface attracted negatively charged micelles or free amphiphilic molecules, which facilitated their aggregation into a bilayer membrane. The bilayer membranes could be closed to form vesicles that have LDHs particles encapsulated. It was also found that an adsorbed compound layer of LSB and SDBS micelles or molecules on the LDHs surface played a key role in the vesicle formation.     

Surfactant-assisted fabrication PbS nanorods, nanobelts, nanovelvet-flowers and dendritic nanostructures at lower temperature in aqueous solution

PbS nanostructures with different morphologies, such as rod-like, belt-like, downy-velvet-flower-like and dendrite-like, were fabricated successfully under varied reaction conditions in aqueous solution at lower temperature by the assistance of surfactant CTAB. Especially, among all the synthesis methods for PbS nanocrystals, this is the first report using basic acetate of lead, which was formed at initial reaction stage, as a precursor to control the crystal nucleation rate. This synthesis method is a promising one to metal sulfide for its easy control, low-cost and large-scale production. X-ray powder diffraction (XRD), transmission electron microscopy (TEM), selected area electron diffraction (SAED), field-emission scanning electron microscopy (FE-SEM) and UV-visible spectrophotometer (UV-vis) were used to characterize the products. A rational mechanism is proposed and three control factors to the crystal directional growth are also concluded.     

Synthesis and photophysics of leadsulphide nanocrystallites

Nanoparticles of lead sulphide have been stabilized in the presence of excess Pb²⁺ in aqueous basic medium by a simple chemical route of synthesis. These PbS nanoparticles were synthesized very conveniently at room temperature using hexametaphosphate as stabilizer. These nanoparticles have an absorption extending into the NIR region. A significant quantum confinement effect made the bandgap of lead sulphide nanoparticles produce a blue shift from 0.41 eV to about 1.5 eV. The size and morphology of the particles were studied by TEM. Particles were relatively small sized (about 6 nm) having narrow size distribution. XRD data analysis indicate that the product is a mixture of PbS, PbO and Pb(OH)₂. Both XRD pattern and HRTEM images confirm the crystalline structure of lead sulphide crystals. IR spectroscopy indicates the formation of PbS. PbS nanoparticles were fairly stable and could be stored for about three weeks at room temperature and for about two months at 5°C without agglomeration. These particles were photoactive and sensitized the reaction of aniline by light leading to the formation of azobenzene.     

薄层法研究十二烷基苯磺酸钠对硝基苯/水界面电子转移的影响

用薄层法研究了阴离子表面活性剂十二烷基苯磺酸钠(SDBS)对硝基苯/水界面电子转移的影响. 实验结果表明, 随着水相中十二烷基苯磺酸钠浓度的增加, 有机相中十甲基二茂铁(DMFc)和水相中Fe(CN)₆^3-发生的界面双分子反应的阴极平台电流呈现递减趋势, 但是界面双分子反应速率常数却呈递增趋势. 这是由于阴离子表面活性剂十二烷基苯磺酸钠在硝基苯/水界面形成了修饰层, 影响了界面双电层结构. SDBS在液/液界面的吸附为Langmuir吸附.     

Controlled synthesis of bionic microstructure PbS crystals by mixed cationic/anionic surfactants

Hexagonal starfish-like PbS crystals have been synthesized by the reaction of lead acetate and thioacetamide (TAA) controlled by mixture of cetyltrimethylammonium bromide/sodium dodecyl sulfate (STAB/SDS) at the molar ratio of 5: 1 through a hydrothermal process at 80°C. It has been found that the hexagonal starfish-like PbS single crystal is in cubic phase, and the six arms of the star extend along the six 〈100〉 directions. By changing reaction conditions, such as the molar ratio of CTAB/SDS, temperature, and reaction time, the amounts of TAA and lead sources, the morphology and structure of the PbS crystals can be controlled. Furthermore, possible formation mechanism was preliminarily illustrated. The room-temperature photoluminescence spectra in solid state of the PbS single crystals obtained after different reaction times were investigated, which demonstrated that the PbS single crystals presented excellent optical properties. This work may open a novel route to the shaped-controllable synthesis of semiconductor crystals with various morphologies.     

Fabrication of PbS Nanoparticles Embedded in Silica Gel by Reverse Micelles and Sol-Gel Routes

PbS doped-silica gels showing a visible absorption onset were prepared by the sol-gel method. PbS nanoparticles with strong quantum-confinement effect were obtained from sodium sulfide and lead nitrate by the reverse micelle method. Chemical parameters such as the water/surfactant and the [Pb²⁺]/[S²⁻] ratios play a very important role in the PbS particle size and in their absorption threshold. The PbS nanoparticles were dispersed in a hydrolyzed solution of TEOS and converted to homogeneous gels after heating. The absorption threshold of PbS doped-gel is blue shifted compared to the one of the as-prepared PbS particles. The non-linear optical properties of the PbS nanoparticle solution were measured by degenerate four-wave mixing and theX ⁽³⁾ value was estimated to be 1.95 10⁻¹¹ esu.     

One-pot synthesis and self-assembly of copper phthalocyanine nanobelts through a water-chemical route

A water-chemical route to synthesize copper phthalocyanine (CuPC) is reported in this paper. The molecules were self-assembled into regular beta-CuPC single-crystal nanobelts simultaneously. The molecular structure of CuPC in the nanobelts was characterized by UV-vis absorption spectroscopy, MALDI-TOF-MS, and elemental analysis. The morphology and crystal phase of the nanobelts were investigated by electron microscopy and X-ray diffraction, respectively. Crucial factors for the formation of CuPC nanobelts were also investigated. The cooperative effect of the surfactant and copper powder was important for the formation of CuPC. The CuPC nanobelts were obtained through a self-assembly process. In addition, a phase transition process, which resulted in the formation of beta-CuPC single-crystal nanobelts, took place with prolonged time.