亚稳态MInS2(M=Ag,Cu)花状微米球的热分解法合成及其生长机理

采用热分解法制备了三维的亚稳态正交相AgInS_2和六方相CuInS_2花状微米球。通过X射线衍射(XRD),场发射扫描电子显微镜(FESEM)等对样品进行表征,对AgInS_2的光催化性能进行了评估,并借助于热重-差热分析(TG-DTA)等手段研究了亚稳态正交相AgInS_2和六方相CuInS_2花状微米球的生长机理。实验结果表明,反应温度和反应物中金属离子的投料比对生成纯相的MIn S2均有影响,而AgInS_2花状微米球能在可见光下较好地催化降解亚甲基蓝。     

亚稳态MInS2(M=Ag，Cu)花状微米球的热分解法合成及其生长机理

采用热分解法制备了三维的亚稳态正交相AgInS₂和六方相CuInS₂花状微米球。通过X射线衍射（XRD）,场发射扫描电子显微镜（FESEM）等对样品进行表征,对AgInS₂的光催化性能进行了评估,并借助于热重分析（TG-DTA）等手段研究了亚稳态正交相AgInS₂和六方相CuInS₂花状微米球的生长机理。实验结果表明,反应温度和反应物中金属离子的投料比对生成纯相的MInS₂均有影响,而AgInS₂花状微米球能在可见光下较好地催化降解亚甲基蓝。     

Integrated synthesis and ripening of AgInS2 QDs in droplet microreactors: An update fluorescence regulating via suitable temperature combination

Aqueous phase synthesized ternary I–III–VI₂ Quantum dots (QDs) are getting more and more attention in biology researches, for their good biocompatibility and easy-to-adjust fluorescence properties. However, the quantum yield (QY) of these aqueous phase synthesized QDs are often pretty low, which seriously hindered their further applications in this field. In general, the ripening of the QDs helps to enhance their QY, closely related to the ripening temperature. But it is still hard to precisely control the fluorescence performance of the QDs products, due to the difficulties in precise temperature control and cumbersome temperature adjusting operations in batch reactors. Here we proposed an integrated droplet microfluidic chip for the automated and successive AgInS₂ QDs synthesis and ripening, with both temperatures controlled independently, precisely but easily. Taking advantage of the space-time transformation of the droplet microfluidic chips, the suitable temperature combination for AgInS₂ QDs synthesis and ripening was studied, and the high-performance AgInS₂ QDs were obtained. In addition, the reason for the decrease of QY of AgInS₂ QDs at higher ripening temperature was also explored.     

Solid-state chemistry on a surface and in a beaker: Unconventional routes to transition metal chalcogenide nanomaterials

This article focuses on two different approaches to create nanoscale transition metal chalcogenide materials. First, we used chemical nanofabrication, a combination of top-down patterning and bottom-up solid-state synthesis, to achieve control over the shape, size, and ordering of the patterned nanomaterials. We demonstrated orientational control over nanocrystals within sub-300 nm patterns of MoS₂ and formed free-standing nanostructures of crystalline NiS₂. In addition, crossed line arrays of mixed metal chalcogenide nanostructures were achieved, and TaS₂ nanopatterns were made by the chemical transformation of tantalum oxide templates. Second, we developed a one-pot procedure using molecular precursors to synthesize two-dimensional NbSe₂, TaS₂ and TaSe₂ nanoplates and one-dimensional NbSe₂ wires depending on the relative amount of surfactants in the reaction mixture. Prospects for these transition metal chalcogenide nanomaterials with controlled shapes and morphologies will be discussed.     

Room‐Temperature Synthesis of Cu2−xE (E=S,Se) Nanotubes with Hierarchical Architecture as High‐Performance Counter Electrodes of Quantum‐Dot‐Sensitized Solar Cells

Copper chalcogenide nanostructures (e.g. one‐ dimensional nanotubes) have been the focus of interest because of their unique properties and great potential in various applications. Their current fabrications mainly rely on high‐temperature or complicated processes. Here, with the assistance of theoretical prediction, we prepared Cu_2?xE (E=S, Se) micro‐/nanotubes (NTs) with a hierarchical architecture by using copper nanowires (Cu NWs), stable sulfur and selenium powder as precursors at room temperature. The influence of reaction parameters (e.g. precursor ratio, ligands, ligand ratio, and reaction time) on the formation of nanotubes was comprehensively investigated. The resultant Cu_2?xE (E=S, Se) NTs were used as counter electrodes (CE) of quantum‐dot‐sensitized solar cells (QDSSCs) to achieve a conversion efficiency (η) of 5.02 and 6.25 %, respectively, much higher than that of QDSSCs made with Au CE (η=2.94 %).     

Synthesis of AgInS2 QDs in droplet microreactors: Online fluorescence regulating through temperature control

We designed a temperature-controllable droplet microreactor with more precisely temperature control and shorter synthesis time for water-soluble AgInS₂ QDs synthesis. When reaction temperature increased from 30 ℃ to 70 ℃, QDs fluorescence peak constantly red-shifted from 590 nm to 720 nm along with enhanced fluorescence QY and intensity, we can get products with the maximum fluorescence intensity and the QY of 8.8% at 70 ℃.     

Flower-like boehmite nanostructure formation in two-steps

Reaction between AlCl₃ and TEA (triethanolamine) gave Al(OH)₃ colloidal nanocrystals that were precursors to nucleation and growth of boehmite under hydrothermal conditions. Transition electron microscopic (TEM) observations revealed that flower-like nanostructures were produced through a binary self-assembly system. In the first stage, nanostrips organize themselves to form a bundle, because of NH₄⁺ and TEA. In the second stage, the bundles form flower-like nanostructures due to the interaction of nitrate with TEA. The size of the nanopetals (length 100–200?nm; width 100–150?nm; and thickness 20–70?nm) was measured through TEM. X-ray diffraction and Brunauer–Emmett–Teller (BET-N₂) results demonstrate that the obtained nanostructures were composed of a pure AlOOH phase with a surface area of 160?m^2?g^?1. The effect of Cl?ˉ on the growth of boehmite 3-D nanoarchitectures in the presence of NO₃ˉ was also investigated.     

Enhanced growth of crystalline-amorphous core-shell silicon nanowires by catalytic thermal CVD using in situ generated tin catalyst

In this work,we prepared silicon nanowires(Si NWs) on both fluorine-doped SnO 2(FTO) coated glass substrate and common glass substrate by catalytic thermal chemical vapor deposition(CVD) using indium film as the catalyst.It is confirmed that indium can catalyze the growth of Si NWs.More importantly,we found that tin generated in situ from the reduction of SnO 2 by indium can act as catalyst,which greatly enhances the growth of Si NWs on FTO substrate.The obtained Si NWs have a uniform crystalline-amorphous core-shell structure that is formed via vapor-liquid-solid and vapor-solid growth of silicon sequentially.This work provides a strategy to prepare Si NWs in high yield by catalytic thermal CVD using the low melting point metal catalysts.     

Metal Bromide Controlled Interfacial Aromatization Reaction for Shape‐Selective Synthesis of Palladium Nanostructures with Efficient Catalytic Performances

Herein, the effect of diverse metal bromides for the shape evolution of palladium nanostructures (Pd NS) has been demonstrated. Aromaticity‐driven reduction of bromopalladate(II) is optimized to reproducibly obtain different Pd NS at the water/organic layer interface. In this soft interfacial strategy, a redox potential driven reaction has been performed, forming the thermodynamically more stable (>10⁴‐fold) PdBr₄^2? precursor from PdCl₄^2? by adding extra metal bromides. In the process, the reductant, Hantzsch dihydropyridine ester (DHPE), is aromatized. Interestingly, alkali metal bromides devoid of coordination propensity exclusively evolve Pd nanowires (Pd NWs), whereas in the case of transition metal bromides the metal ions engage the ‘N’ donor of DHPE at the interface, making the redox reaction sluggish. Hence, controlled Pd nanoparticles growth is observed, which evolves Pd broccolis (Pd NBRs) and Pd nanorods (Pd NRs) at the interface in the presence of NiBr₂ and CuBr₂, respectively, in the aqueous solution. Thus, the effect of diverse metal bromides in the reaction mixture for tailor‐made growth of the various Pd NS is reported. Among the as‐synthesized materials, the Pd NWs stand to be superior catalysts and their efficiency is almost 6 and 2.5 times higher than commercial 20 % Pd/C in the electrooxidation of ethanol and Cr^VI reduction reaction by formic acid, respectively.     

In Situ Self-Assembled J-Aggregate Nanofibers of Glycosylated Aza-BODIPY for Synergetic Cell Membrane Disruption and Type I Photodynamic Therapy

The in situ self-assembly of exogenous molecules is a powerful strategy for manipulating cellular behavior. However, the direct self-assembly of photochemically inert constituents into supramolecular nano-photosensitizers (PSs) within cancer cells for precise photodynamic therapy (PDT) remains a challenge. Herein, we developed a glycosylated Aza-BODIPY compound ( LMBP ) capable of self-assembling into J-aggregate nanofibers in situ for cell membrane destruction and type I PDT. LMBP selectively entered human hepatocellular carcinoma HepG2 cells and subsequently self-assembled into intracellular J-aggregate nanovesicles and nanofibers through supramolecular interactions. Detailed studies revealed that these J-aggregate nanostructures generated superoxide radicals (O₂⁻⋅) exclusively through photoinduced electron transfer, thus enabling effective PDT. Furthermore, the intracellular nanofibers exhibited an aggregation-induced retention effect, which resulted in selective toxicity to HepG2 cells by disrupting their cellular membranes and synergizing with PDT for powerful tumor suppression efficacy in vivo.     

Si衬底上生长的铁硅化合物结构和取向分析

采用分子束外延法分别在650-920 ℃的Si（110）和920 ℃的Si（111）衬底表面生长出铁的硅化物纳米结构,并主要分析了920 ℃高温下纳米结构的形貌、组成相及其与Si 衬底的取向关系. 扫描隧道显微镜（STM）研究表明,920 ℃高温下,Si（110）衬底上生长的铁硅化合物完全以纳米线的形式存在,且其尺寸远大于650 ℃低温下外延生长的纳米线尺寸;Si（111）衬底上生长出三维岛和薄膜两种形貌的铁硅化合物,其中三维岛具有金属特性且直径约300 nm、高约155 nm,薄膜厚度约2 nm. 电子背散射衍射研究表明920 ℃高温下Si（110）衬底上生长的纳米线仅以β-FeSi₂的形式存在,且β-FeSi₂相与衬底之间存在唯一的取向关系：β-FeSi₂（101）//Si（111）;β-FeSi₂ [010]//Si[110];Si（111）衬底上生长的三维岛由六方晶系的Fe₂Si 相组成,Fe₂Si 属于164 空间群,晶胞常数为a=0.405 nm,c=0.509 nm;与衬底之间的取向关系为Fe₂Si（001）∥Si（111）和Fe₂Si[120]//Si[112].     

Fabrication of Hierarchically Structured MOF‐Co3O4 on Well‐aligned CuO Nanowire with an Enhanced Electrocatalytic Property

Engineering appropriate shape and size of three‐dimensional inorganic nanostructures materials is of one the main critical problems in pursuing high‐performance electrode materials. Herein, we fabricate a metal‐organic framework derived cobalt oxide (Co₃O₄) are grown on copper oxide nanowire (CuO NWs) supported on the surface of 3D copper foam substrate. The highly aligned CuO NWs were prepared by using electrochemical anodization of copper foam in ambient temperature and followed by MOF Co₃O₄ was grown via a simple in situ solution deposition then consequent calcination process. The obtained binder‐free 3D CuO NWs@Co₃O₄ nanostructures were further characterized by using X‐ray diffraction, X‐ray photoelectron spectroscopy, field‐emission scanning electron microscopy, and transmission electron microscopy. Furthermore, electrochemical sensing of glucose was studied by using Cyclic Voltammetry, and chronoamperometry techniques. Interestingly, 3D CuO NWs@Co₃O₄ electrode exhibits excellent performance for the oxidation of glucose compared with individual entities. The proposed sensor shows wide linear ranges from 0.5 μM to 0.1 mM with the sensitivity of 6082 μA/μM and the lowest detection limit (LOD) of 0.23 μM was observed with the signal to noise ratio, (S/N) of 3. The superior catalytic oxidation of glucose mainly is endorsed by the excellent electrical conductivity and synergistic effect of the Co₃O₄ and CuO NWs.     

Investigation of the growth parameters of hydrothermal ZnO nanowires for scale up applications

Zinc oxide nano-wires (ZnO NWs) are synthesized reproducibly with high yield via a low temperature hydrothermal technique. The influence of the growth duration time, growth temperature, zinc precursor and base concentration of Na₂CO₃ on the morphology of NWs is investigated. The growth products are characterised using scanning electron microscopy (SEM), Transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and photoluminescence (PL). SEM analysis shows that the optimum growth temperature is 140 °C and finds that length and diameter of ZnO NWs have a relationship with growth duration time and base concentrations of Na₂CO₃. In addition, it is reported that a high (～90%) yield of ZnO NWs can be synthesised via using any of three different precursors: zinc chloride, zinc acetate and zinc nitrate. TEM and XRD results indicate the high purity and the single crystalline nature of the ZnO NWs. XPS confirms the absence of sodium contaminants on the surface and indicates a near flat band surface condition. PL shows a large visible band in the yellow part of the spectrum, and a small exciton emission peak, indicating a large defect concentration, which is reduced after annealing in air.     

A template self-assembly strategy to synthesize free-standing TiO2-MO (M = Mg, Co, Ni, Cu or Zn) colloidal films

A series of binary free-standing colloidal films, TiO₂-MO (M = Mg, Co, Ni, Cu and Zn) have been synthesized via a self-assembly technology, utilizing sodium dodecyl sulfonate (SDS) as template and the mixture of titanium butoxide and MCl₂ as precursor. X-ray diffraction (XRD) and transmission electron microscope (TEM) have been employed to characterize TiO₂-MO samples. Results show that TiO₂-MO films are mainly composed by well-ordered nanostructures (e.g. mesoporous particles and lamellar pieces) and more importantly, the increased Ti(OC₄H₉)₄ precursor have significant effect on modifying the as-synthesized nanostructures. A structural model based on SDS micellar template, the complex metallic oxide precursor and charge-density matching between the template and precursor has been proposed. Remarkably, this template self-assembly method has a potential to design a variety of functional multicomponent materials with high-ordered nanostructures, such as high gas sensing SnO₂-ZnO films.     

Silica nanowires: Growth,integration, and sensing applications

This review (with 129 refs.) gives an overview on how the integration of silica nanowires (NWs) into micro-scale devices has resulted, in recent years, in simple yet robust nano-instrumentation with improved performance in targeted application areas such as sensing. This has been achieved by the use of appropriate techniques such as di-electrophoresis and direct vapor-liquid-growth phenomena, to restrict the growth of NWs to site-specific locations. This also has eliminated the need for post-growth processing and enables nanostructures to be placed on pre-patterned substrates. Various kinds of NWs have been investigated to determine how their physical and chemical properties can be tuned for integration into sensing structures. NWs integrated onto interdigitated micro-electrodes have been applied to the determination of gases and biomarkers. The technique of directly growing NWs eliminates the need for their physical transfer and thus preserves their structure and performance, and further reduces the costs of fabrication. The biocompatibility of NWs also has been studied with respect to possible biological applications. This review addresses the challenges in growth and integration of NWs to understand related mechanism on biological contact or gas exposure and sensing performance for personalized health and environmental monitoring.

Silica nanowires decorated micro-electrodes for sensing application

     

Indirect Transformation of Coordination‐Polymer Particles into Magnetic Carbon‐Coated Mn3O4 (Mn3O4@C) Nanowires for Supercapacitor Electrodes with Good Cycling Performance

Carbon‐coated Mn₃O₄ nanowires (Mn₃O₄@C NWs) have been synthesized by the reduction of well‐shaped carbon‐coated bixbyite networks and characterized by TEM, X‐ray diffraction, X‐ray photoelectron spectroscopy, and electrochemical experiments. To assess the properties of 1D carbon‐coated nanowires for their use in supercapacitors, cyclic voltammetry and galvanostatic charging–discharging measurements were performed. Mn₃O₄@C NWs could be charged and discharged faster and had higher capacitance than bare Mn₃O₄ nanostructures and other commercial materials. The capacitance of the Mn₃O₄@C NWs was 92 % retained after 3000 cycles at a charging rate of 5 A g^?1. This improvement can be attributed to the carbon shells, which promote fast Faradaic charging and discharging of the interior Mn₃O₄ core and also act as barriers to protect the inner core. These Mn₃O₄@C NWs could be a promising candidate material for high‐capacity, low‐cost, and environmentally friendly electrodes for supercapacitors. In addition, the magnetic properties of the as‐synthesized samples are also reported to investigate the influence of the carbon coating.     

Nitrate ion promoted formation of Ag nanowires in polyol processes: a new nanowire growth mechanism

In polyol processes, it was widely accepted that Ag nanowires (NWs) were formed via uniaxial growth of multiple twinned decahedral particles (MTPs) along the {111} facets. Herein, we show that the above MTP uniaxial growth mechanism for growth of nanorods (NRs) and short nanowires (NWs) is different from that for the growth of long Ag NWs. We provide experimental evidence to show that polycrystalline long Ag NWs (up to ~100 μm) could be formed in high yield (~90%) by a completely different growth mechanism via self-assembly of Ag NPs/NRs. Transmission electron microscope (TEM) measurements show that long Ag NWs are composed of crystalline Ag NPs and NRs with multiple crystal orientations, and many NRs have crystalline structures with pentagonal cross section. Solution phase in situ X-ray diffraction (XRD) measurements show that a strained face-centered tetragonal (fct) phase was gradually formed during the formation and growth of long Ag NWs, in addition to the normal face-centered cubic (fcc) phase. The strained fct phase disappears after partial etching by HAuCl(4) and Fe(NO(3))(3). The working conditions for the MTP uniaxial growth mechanism and the current nitrate-promoted self-assembly growth mechanism will be compared and discussed.     

Highly Porous Thermoelectric Nanocomposites with Low Thermal Conductivity and High Figure of Merit from Large‐Scale Solution‐Synthesized Bi2Te2.5Se0.5 Hollow Nanostructures

To enhance the performance of thermoelectric materials and enable access to their widespread applications, it is beneficial yet challenging to synthesize hollow nanostructures in large quantities, with high porosity, low thermal conductivity (κ ) and excellent figure of merit (z T ). Herein we report a scalable (ca. 11.0 g per batch) and low‐temperature colloidal processing route for Bi₂Te_2.5Se_0.5 hollow nanostructures. They are sintered into porous, bulk nanocomposites (phi 10 mm×h 10 mm) with low κ (0.48 W m⁻¹ K⁻¹) and the highest z T (1.18) among state‐of‐the‐art Bi₂Te_3−x Se_x materilas. Additional benefits of the unprecedented low relative density (68–77 %) are the large demand reduction of raw materials and the improved portability. This method can be adopted to fabricate other porous phase‐transition and thermoelectric chalcogenide materials and will pave the way for the implementation of hollow nanostructures in other fields.     

AgInS2纳米粒子的制备及其可见光催化活性

以水为溶剂,硫代乙酰胺为硫源,巯基乙酸为包覆剂,于低温下制备了正交相的AgInS2纳米粒子。用TEM、EDS和XRD对所制备的AgInS2纳米粒子的形貌、组成和晶相进行了表征。并考察了反应时间对AgInS2纳米粒子的晶相及其可见光催化降解活性的影响。结果表明:延长反应时间可以提高AgInS2纳米粒子的结晶性和可见光催化活性。     

Calcination-temperature-dependent gas-sensing properties of mesoporous α-Fe2O3 nanowires as ethanol sensors

The mesoporous α-Fe₂O₃ nanowires (NWs) were successfully synthesized by changing the calcination temperature from 550 to 750 °C (marked NWs-550, NWs-650 and NWs-750) via using SBA-15 silica as the hard templates with the nanocasting method. The characterization results indicated that the bandgap of the as-prepared samples hardly changed and the high BET surface areas changed a little with the calcination temperature from 550 to 750 °C. Mesoporous α-Fe₂O₃ NWs had been found to possess the remarkable gas-sensing performance to ethanol gas. The gas-sensing behavior indicated that α-Fe₂O₃ NWs-650 exhibited the higher response than that of α-Fe₂O₃ NWs-550 and α-Fe₂O₃ NWs-750. The calcination-temperature-dependent gas-sensing properties were mainly attributed to the competition of surface defects and body defects by the crystallization temperature. The lower calcination temperature could create more surface defects to improve the gas-sensing response, while the higher temperature would reduce the body defect and make the charge carriers transport easily. As the result, the suitable calcination temperature was desired to optimize the defects of nanostructures to improve the gas sensitivity.