Facial fabrication of superhydrophobic cellulose film with hierarchical morphologies

Hierarchical CuO spheres were firstly grown on the surface of cellulose film, and then stearic acid (STA) was utilized to decrease surface energy. The cupric ions fixed on the cellulose film transferred to one side and reacted with STA forming cupric stearates. The cupric stearates then self-assembled into nanobelts/nanoribbons and spread over the film, which induces to form hierarchical morphologies. Both sides of CuO modified film are black and superhydrophilic in air; after modification with STA, the film becomes superhydrophobic for both sides, whereas one side is blue and the other side is black showing different morphologies. Water contact angles (WCAs) of the superhydrophobic film for both black and blue sides are 153.9 ± 0.6° and 153.5 ± 0.8°, respectively. Sliding angles (SAs) for both sides are lower than 9.5°, indicating non-sticking superhydrophobic state. More importantly, the superhydrophobic cellulose–CuO–STA film is still superhydrophobic under hydrodynamic impact or pH of 3–11.     

Growth mechanism of penniform BaWO4 nanostructures in catanionic reverse micelles involving polymers

The formation of penniform BaWO4 nanostructures made of nanowires or nanobelts under the direction of a block copolymer in catanionic reverse micelles has been studied in detail. On the basis of the experimental results obtained from the BaWO4 crystallization in aqueous polymer solutions and careful transmission electron microscopy (TEM) observations of BaWO4 nanostructures formed in reverse micelles containing polymers, a detailed two-stage growth mechanism has been proposed for the formation of the penniform nanostructures in reverse micelles, which involves the polymer-controlled shaft formation (Stage 1) and the mixed surfactants-controlled barb growth (Stage 2). During Stage 1, poly(ethylene glycol)-block-poly(methacrylic acid) (PEG-b-PMAA) induced the formation of c-axis-oriented shuttle-like nanocrystals and the subsequent oriented attachment of these shuttle-like nanocrystals resulted in the formation of [100]-oriented shafts with many parallel [001]-oriented pricks. During Stage 2, [001]-oriented nanowires or nanobelts grew gradually from the pricks into barbs, leading to the formation of well-defined penniform BaWO4 nanostructures with the barb morphology essentially determined by the mixing ratio r of the anionic to cationic surfactants (i.e., nanowires were formed at r=1 while nanobelts were formed at r deviating from 1). The current understanding of the growth mechanism of penniform BaWO4 nanostructures in catanionic reverse micelles involving polymers may be potentially applied for designing a new synthesis system for the controlled synthesis of other hierarchical 1D nanostructures with desired architectures.     

静电纺丝技术制备LaCrO4和LaCrO3纳米带及其光催化性质

采用溶胶-凝胶法结合静电纺丝技术制备了PVP/[La(NO3)3|Cr(NO3)3]复合纳米带, 经热处理后得到LaCrO4纳米带和LaCrO3纳米带. 采用TG-DTA, XRD, SEM和EDS等测试手段对样品进行了表征. 结果表明, PVP/[La(NO3)3-Cr(NO3)3]复合纳米带表面光滑, 宽度为(9.1±1.9) μm, 厚度约385 nm; 经600 ℃焙烧后得到单斜独居石型LaCrO4纳米带, 宽度为(2.5±0.5) μm, 厚度约100 nm; 当焙烧温度为650~800 ℃时得到LaCrO3多孔纳米带, 属正交晶系, Pbnm空间群, 经650 ℃焙烧后得到的LaCrO3纳米带呈多孔结构, 带宽为(2.4±0.5) μm, 厚度约90 nm; 经800 ℃焙烧后得到的LaCrO3纳米带部分破碎形成LaCrO3纳米粒子, LaCrO3纳米带宽度约(1.3±0.4) μm, 厚度约90 nm, LaCrO3纳米粒子粒径约80 nm. 以罗丹明B为目标降解物, 研究了不同焙烧温度下产物的光催化性能, 其中800 ℃焙烧后得到的样品在紫外光照射下对罗丹明B的降解效果最好, 光照200 min后罗丹明B的降解率为94.6%.     

简易、可控制备硫化铅纳米带

以硝酸铅和硫代乙酰胺为前体,十二烷基苯磺酸钠（SDBS）扮演了前体和表面活性剂的双重角色,制备出硫化铅纳米带。 采用透射电子显微镜、X射线衍射和光致发光对所制备的纳米带进行了表征。 结果表明,中间产物PbSO4在水热条件下对PbS纳米带的进一步形成主要起到模板作用。 进一步考察了纳米带形成机理,结果表明,中间产物PbSO4对表面活性剂是有制约性的,而当改变中间产物保持条件不变的情况下,模板效应失控,只能得到不规则的微晶体。 实验结果表明,制备硫化铅纳米带反应速度较为缓慢,易于控制,为制备不同形貌纳米带提供了一种有效方法。     

Shape-dependent magnetic properties of low-dimensional nanoscale Prussian blue (PB) analogue SmFe(CN)6.4H2O

Unique nanorods and nanobelts of Prussian blue (PB) analogue SmFe(CN)6.4H2O have been successfully synthesized by using reverse micelles as colloidal soft templates; magnetic studies show that the shape of the low-dimensional nanoscale material is a dominating factor for its coercivity due to the effect of shape anisotropy.     

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.     

表面活性剂模板法制备CeO_2/CuO催化剂用于富氢气氛中CO优先氧化

采用表面活性剂模板法合成了一组不同配比的CeO2/CuO催化剂,使用高分辨透射电子显微镜(HRTEM)、X射线粉末衍射(XRD)、N2吸附脱附和程序升温还原(H2-TPR)等测试手段对催化剂进行了表征,并对其在富氢气氛中CO优先氧化的催化性能进行了研究。结果表明,立方相萤石结构的氧化铈颗粒粒径在4 nm左右,它们聚集成小簇后分散在块状氧化铜的表面;从粒径分布来看所制备的催化剂是逆负载型催化剂。催化性能测试结果显示,CeO2/CuO催化剂中有两种类型吸附位的存在,即由CuO提供的化学吸附位和由氧化铈提供的氧空位,而界面处两种类型吸附位的共存促进了CO的优先氧化。     

High ethanol sensitivity of Palladium/TiO2 nanobelt surface heterostructures dominated by enlarged surface area and nano-Schottky junctions

TiO₂ nanobelts were prepared by the hydrothermal growth method. The surface of the nanobelts was coarsened by selective acid corrosion and functionalized with Pd catalyst particles. Three nanobelt samples (TiO₂ nanobelts, surface-coarsened TiO₂ nanobelts and Pd nanoparticle/TiO₂ nanobelt surface heterostructures) were configured as gas sensors and their sensing ability was measured. Both the surface-coarsened nanobelts and the Pd nanoparticle-decorated TiO₂ nanobelts exhibited dramatically improved sensitivity to ethanol vapor. Pd nanoparticle-decorated TiO₂ nanobelts with surface heterostructures exhibited the best sensitivity, selectivity, working temperature, response/recovery time, and reproducibility. The excellent ethanol sensing performance is attributed to the large surface area and enhancement by Schottky barrier-type junctions between the Pd nanoparticles and TiO₂ nanobelts.     

Large-scale growth of millimeter-long single-crystalline ZnS nanobelts

Millimeter-long single-crystalline hexagonal ZnS nanobelts were grown on specific locations on a wafer scale. This is the first time that the millimeter-scale ZnS nanobelt has been synthesized. The longest nanobelts are about 3 mm. The as-grown nanobelts were characterized by means of field emission scanning electron microscopy, X-ray powder diffraction, high-resolution transmission electron microscopy, and selected area electron diffraction. The results indicate that the ultra-long nanobelts are pure single-crystalline hexagonal ZnS. There are two kinds of ZnS nanobelts existing in the products. One is the nanobelts that have two smooth sides and grow along the [0 0 1] longitudinal direction, and the other is the nanobelts that have one smooth side and one saw-teeth-like side, namely nanosaws, and grow along the [2 1 0] longitudinal direction. A vapor-liquid-solid mechanism is suggested for the lengthwise growth of the ZnS nanobelts (nanosaws) and a vapor-solid mechanism for the side direction growth of the saw-teeth of the nanosaws.     

Chloride Assisted Growth of Aluminum Nitride Nanobelts and Their Enhanced Dielectric Responses

Aluminum nitride (AlN) nanobelts were successfully synthesized in high yield through a chloride assisted vapor-solid process. X-ray diffraction, transmission electron microscopy, and selected area electronic diffraction demonstrate that the as-prepared nanobelts are pure, structurally uniform and single crystalline, and can be indexed to hexagonal wurtzite structure. The micro observations show that there exist no defects in the obtained nanobelts. The growth direction of the nanobelts is along 0001. The frequency spectra of the relative dielectric constant and of the dielectric loss were measured in the frequency range of 50 Hz to 5 MHz. Analysis of these spectra indicates that the interface in samples has great influence on the dielectric behavior of samples. As compared with AlN micropowders, AlN nanobelts have much higher relative dielectric constant, especially at low frequencies at room temperature.     

A Systematic Study of ZnO/CuO Core/Shell Nanostructures Pegylated by Microwave Assistant Reverse Micelles (RM) Method

In this work we synthesized ZnO/CuO nanostructures pegylated by simple and fast microwave method assistant reverse micelles, Reverse micelles protocol creates many advantages in stability, particle size control, morphology, density, loading level, distribution, uniformity, charge and purification. Based on the statistical results ZnO/CuO nanostructures placed in the hydrophilic substrate. The effect of microwave and concentration of surfactant on the surface area, pore diameter and pore volume of the final product was systematically studied using Taguchi technique. ZnO/CuO core/shell pegylated nanostructures, indicating a ZnO as core and CuO as shell and continuous micelles chains around this structures. Products were characterized by UV–Vis spectra, X-ray diffraction, scanning electron microscopy, Dynamic light scattering, Energy-dispersive X-ray spectroscopy, transmission electron microscopy and nitrogen adsorption (i.e. Brunauer–Emmett–Teller surface area analysis).     

低温制备具有强荧光性能三氧化钼纳米带水溶胶

通过过氧化途径,在低温(100℃)且不使用模板和有机溶剂的条件下,成功制备了具有良好荧光性能的三氧化钼(MoO3)纳米带水溶胶.利用X射线衍射仪(XRD)、透射电子显微镜(TEM)、高分辨透射电子显微镜(HRTEM)、荧光光谱仪、荧光显微镜等表征手段对所制备溶胶的结构及性能进行了表征.结果显示,溶胶是由长度约为100μm,宽度为50nm到100nm,厚度小于10nm的MoO3纳米带组成.所制备的溶胶烘干后可以得到大面积的MoO3纳米带薄膜,薄膜具有很好的韧性.荧光光谱图及荧光显微镜照片显示,纳米带溶胶及干燥后所得到的自支撑(free standing)纳米带薄膜均具有良好的荧光性能,表明其在光学成像、传感及LED等方面具有很好的应用前景.     

Synthesis and formation mechanism of TiO2/Al2O3 nanobelts by electrospinning

Poly(vinyl pyrrolidone) (PVP)/[Ti(SO₄)₂ + Al(NO₃)₃] composite nanobelts were prepared via electrospinning technology, and TiO₂/Al₂O₃ nanobelts were fabricated by calcination of the prepared composite nanobelts. The samples were characterized by thermogravimetric-differential thermal analysis (TG-DTA), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and Scanning electron microscopy (SEM). XRD results show that the composite nanobelts were amorphous in structure, and pure phase TiO₂/Al₂O₃ nanobelts were obtained by calcination of the relevant composite nanobelts at 950°C for 8 h. SEM analysis indicates that the surface of as-prepared composite nanobelts was smooth, the widths of the composite fibers were in narrow range, and the mean width was ca. 8.9 ± 2.1 μm, thickness was about 255 nm, and there is no cross-linking among nanobelts. The width of TiO₂/Al₂O₃ nanobelts was ca. 1.3 ± 0.1 μm and the thickness was about 105 nm. TG-DTA analysis reveals that the N,N-dimethylformamide (DMF), organic compounds and inorganic salts in the composite nanobelts were decomposed and volatilized totally, and the weight of the sample kept constant when sintering temperature was above 900°C, and the total weight loss percentage was 81%. FTIR analysis manifests that crystalline TiO₂/Al₂O₃ nanobelts were formed at 950°C. The possible formation mechanism of the TiO₂/Al₂O₃ nanobelts was preliminarily discussed.     

Facile Preparation and Visible-light Photocatalysis Enhancement of N-Doped β-TiO2 Nanobelts

A facile preparation of nitrogen-doped β-TiO₂(N-doped β-TiO₂) nanobelts and their visible-light photocatalytic activity were reported. The preparation of N-doped β-TiO₂ nanobelts consisted of cation-exchange between layered sodium titanate nanobelts and NH₄⁺ in aqueous solution at room temperature and subsequent calcination in air. Such a calcination treatment is beneficial to the formation of monoclinic N-doped β-TiO₂ nanobelts. Various measurement results indicate that not only were the nitrogen atoms doped into the lattice of β-TiO₂ nanobelts resulting in a strong visible-light absorption, but also a large number of defects were caused by them in the lattice, increasing the stability of β-TiO₂. The photocatalysis enhancement of N-doped β-TiO₂ nanobelts for the photodegradation of Rhodamine B was demonstrated.     

Catalyst-assisted vapor-liquid-solid growth of single-crystal Ga2O3 nanobelts

Mass production of quasi-one-dimensional gallium oxide nanobelts is accomplished through graphite-thermal reduction of a mixture of gallium oxide powders and SnO2 nanopowders under controlled experimental conditions. Sn nanoparticles are located at or close to the tips of the nanobelts and served as the catalyst for the nanobelt growth by a vapor-liquid-solid mechanism. The morphology and microstructure of the nanobelts were characterized by scanning electron microscopy and high-resolution transmission electron microscopy. The Ga2O3 nanobelts grow along the [104] direction, the widths ranged from several tens to several hundreds of nanometers, and the lengths ranged from several tens to several hundreds of micrometers. The growth of Ga2O3 nanobelts is initiated by Sn nanoparticles via a catalyst-assisted vapor-liquid-solid process, which makes it possible to control the sizes of Ga2O3 nanobelts.     

Controlled synthesis of gold nanobelts and nanocombs in aqueous mixed surfactant solutions

Well-defined gold nanobelts as well as unique gold nanocombs made of nanobelts were readily synthesized by the reduction of HAuCl4 with ascorbic acid in aqueous mixed solutions of the cationic surfactant cetyltrimethylammonium bromide (CTAB) and the anionic surfactant sodium dodecylsulfonate (SDSn). Single-crystalline gold nanobelts grown along the <110> and <211> directions were prepared in mixed CTAB-SDSn solutions at 4 and 27 degrees C, respectively. Furthermore, single-crystalline gold nanocombs consisting of a <110>-oriented stem nanobelt and numerous <211>-oriented nanobelts grown perpendicularly on one side of the stem were fabricated by a two-step process with temperature changing from 4 to 27 degrees C. It was proposed that the mixed cationic-anionic surfactants exerted a subtle control on the growth of gold nanocrystals in solution due to the cooperative effect of mixed surfactants. This synthetic strategy may open a new route for the mild fabrication and hierarchical assembly of metal nanobelts in solution. The obtained gold nanobelts showed good electrocatalytic activity toward the oxidation of methanol in alkaline solution; in particular, the electrode modified with the nanobelts obtained at 27 degrees C exhibited an electrocatalytic activity considerably higher than normal polycrystalline gold electrode. Moreover, the gold nanobelts were used as the surface-enhanced Raman scattering (SERS) substrate for detecting the enhanced Raman spectra of p-aminothiophenol (PATP) molecules, and the gold nanobelts obtained at 4 degrees C exhibited an unusual larger enhancement of the b2 modes relative to the a1 modes for the adsorbed PATP molecules.     

图案化锥形氧化锌纳米带的原位热氧化法制备与发光性质

采用光刻技术制备出图案的锌膜,所得锌膜与纯氧在700℃氧化反应10 min,在锌膜的表面上原位生长出具有图案的锥形ZnO纳米带阵列,实现了ZnO纳米带生长位置的可控生长。锌膜上得到的锥形ZnO纳米带为单晶六方纤锌矿结构,长度在1～4μm,纳米带根部和顶部的宽度分别在300～700 nm和100～300 nm。提出了锥形ZnO纳米带的可能生长机理。在波长为300nm光的激发下,发现了锌膜上锥形ZnO纳米带具有发光峰位于395 nm弱的紫外光发光和510 nm强的蓝绿光发光,它们分别起源于ZnO宽带隙的激子发射以及表面上离子化氧空位中的电子与价带中光激发的空穴之间的复合。     

Strongly birefringent pb3o2cl2 nanobelts

Orthorhombic Pb3O2Cl2 (mendipite) nanobelts micrometers in length and tens of nanometers wide were synthesized by a solventless thermolysis of a single-source precursor in the presence of capping ligands. The nanobelts are single crystals elongated preferentially in the [010] direction. Pb3O2Cl2 is a birefringent material due to its anisotropic crystal structure. The nanobelts exhibit birefringence enhanced by 1 order of magnitude as a result of their small size and belt geometry exceeding the birefringence of naturally occurring minerals, including CaCO3 and TiO2. The preferential elongation of the nanobelts in the [010] direction contributes to this enhancement.     

Novel bulk synthesis of magnesium oxide nanobelts networks by microwave hydrothermal route

Novel magnesium oxide (MgO) nanobelt structures were successfully synthesized on a large scale, low cost and catalyst free by a microwave hydrothermal route using the magnesium metal and potassium hydroxide precursors at 200 °C for 10 min. The synthesized MgO nanobelts were systemically characterized by power X-ray diffraction (XRD), scanning electron microscopy, energy dispersion spectroscopy and transmission-high resolution electron microscopy. The XRD results indicate that the MgO nanobelts have the well-crystalline cubic phase. The detailed morphological studies revealed that the synthesized products were nanobelts and were grown in large quantity. The optical energy gap of MgO nanobelts was found to be 3.1 eV. The photoluminescence spectra of the MgO nanobelts show a strong and broad green emission band, a weak ultraviolet emission band, and a weak red emission band. This novel method will open new dimensions for synthesized 1-D metal oxide and can be easily extended to the synthesis and assembly of other inorganic nanocrystals.     

表面修饰的钒氧化物纳米带上甲苯选择氧化反应

采用声化学水热法制备了V₂O₅纳米带,并将十六烷基膦酸负载在它和块状V₂O₅表面上,以修饰催化剂表面,通过调变催化剂中晶格氧活动性以及表面酸碱性来控制其催化甲苯氧化产物的选择性.结果表明,V₂O₅纳米带具有较强的晶格氧活动性,与普通块状V₂O₅相比,甲苯转化率更高,但苯甲醛和苯甲酸的总选择性下降.经过表面修饰后,V₂O₅纳米带的催化活性以及苯甲醛、苯甲酸总选择性增加;而块状V₂O₅上苯甲醛、苯甲酸总选择性更高,但催化活性显著下降.