Assistance Of Template Research Articles

Designing Heterogeneous 1D Nanostructure Arrays Based on AAO Templates for Energy Applications.

In order to fulfill the multiple requirements for energy production, storage, and utilization in the future, the conventional planar configuration of current energy conversion/storage devices has to be reformed, since technological evolution has promoted the efficiency of the corresponding devices to be close to the theoretical values. One promising strategy is to construct multifunctional 1D nanostructure arrays to replace their planar counterparts for device fabrication, ascribing to the significant superiorities of such 1D nanostructure arrays. In the last three decades, technologies based on anodic aluminium oxide (AAO) templates have turned out to be valuable meaning for the realization of 1D nanostructures and have attracted tremendous interest. In this review, recent progress in energy-related devices equipped with heterogeneous 1D nanostructure arrays that fabricated through the assistance of AAO templates is highlighted. Particular emphasis is given on how to develop efficient devices via optimizing the componential and morphological parameters of the 1D nanostructure arrays. Finally, aspects relevant to the further improvement of device performance are discussed.

Morphology controlled syntheses of Cu-doped ZnO, tubular Zn(Cu)O and Ag decorated tubular Zn(Cu)O microcrystals for photocatalysis

Without any assistance of surfactant and/or template the hexagonal prism-shaped Cu2+-doped ZnO (Zn(Cu)O) microcrystals with twinned structures were easily synthesized by one-step co-precipitating under atmospheric pressure and moderate temperature, in which Cu2+ ion was used as the dopant and the morphology controller. Because Cu2+ ions can be adsorbed on the (0001) and {101¯1} planes the growth on these planes was restrained, resulting in the formation of Zn(Cu)O microcrystals with stubby hexagonal prism shape. Meanwhile, the twinned structure Zn(Cu)O microcrystals were obtained via the electrostatic interaction between adsorbed Cu2+ ion and two (0001¯) negative planes. When twinned structure Zn(Cu)O sample was etched by NaOH solution the (0001) polar planes at two ends of Zn(Cu)O crystal were dissolved via forming Zn(OH)42− complex ion, but the non-polar {0110} planes did not. As a result, the tubular structure Zn(Cu)O microcrystals (T-Zn(Cu)O) were obtained in the absence of template and/or specific protective agent. The metallic Ag decorated tubular Zn(Cu)O (T-Zn(Cu)O/Ag) samples were prepared by auto-catalyzed deposition reaction. The morphological, structural, photoluminescence, as well as photocatalytic properties of Zn(Cu)O, T-Zn(Cu)O and T-Zn(Cu)O/Ag samples were investigated and the results indicated that the Zn(Cu)O sample with a very small amount of doped Cu2+ ion showed higher photocatalytic activity than ZnO. Tubular structure Zn(Cu)O samples showed moderately enhanced photocatalytic activities compared to corresponding Zn(Cu)O samples. By decorating metallic Ag on the surfaces the T-Zn(Cu)O/Ag samples exhibited distinctly enhanced photocatalytic activities due to the contribution of Schottky barrier and intensive light absorption in Vis and NIR regions.

Gelatin-assisted sol–gel derived TiO2 microspheres for hydrogen storage

TiO2 is an important photocatalyst candidate for solar energy or hydrogen energy harvesting. Creation of porous structures or high surface area within TiO2 microspheres may potentially address the challenge to improve their efficiency. In present work, we report the sol–gel fabrication of mesoporous TiO2 microspheres that assembled from nanoparticles with the assistance of gelatin template. The phase structure, morphology, and mesoporous characteristics were analyzed by X-ray diffraction, transmission electron microscopy, and BET measurements. Particularly, the gelatin-assisted fabricated TiO2 nanoparticles (∼10–20 nm) were achieved to assemble TiO2 microspheres with diameters of 0.2–0.5 μm, which yielded a typical type-IV BET isotherm curve (N2 hysteresis loop) with a large surface area of 98.3 m2/g and a small pore size of 11.9 nm. A simplified model was proposed to investigate the effect mechanism of gelatin on the formation of TiO2 mesoporous microspheres. The room temperature pressure-dependent hydrogen evolution of the gelatin-assisted fabricated TiO2 nanostructures has also been investigated, suggesting that gelatin favors high surface area and improves the hydrogen storage performance, and the achieved TiO2 microspheres could be potential candidates to be utilized as the photocatalyst for hydrogen evolution.

Facile synthesis of zinc–iron mixed oxide/carbon nanocomposites as nanocatalysts for the degradation of methylene blue

Zinc–iron mixed oxide/carbon nanocomposites were synthesized by the pyrolysis of ferrocenium, zinc acetate, and glucose without the assistance of template or surfactant. The as-prepared zinc–iron mixed oxide/carbon nanocomposites exhibited good photocatalytic property over methylene blue under UV light.

Hollow Tin Dioxide Microspheres With Multilayered Nanocrystalline Shells for Pseudocapacitor

Nanocrystalline SnO2 is successfully assembled into highly-ordered hollow microspheres by a facile procedure consisting of hydrothermal synthesis and assistance of templates, then high temperature calcination. The structures consist of highly crystalline grains with hexagonal shape and about 11nm mean size. Kirkendall effect directs the diffusion of SnO2 nanocrystals and carbon dioxide and causes the formation of hollow SnO2 spheres. Effect of the concentration of Sn precursor and acid value on the SnO2 morphology and SnO2 electrochemistry properties for pseudocapacitor are employed. Electrochemical measurements demonstrate that the maximum specific capacitance of hollow SnO2 microspheres is 178.86Fg−1 at a scan rate of 1mVs−1 in 1M KOH solution and originated from Faradaic redox reactions. Also the specific capacitance only decays 4.8% from 150 cycles to 200 cycles and keeps constant from 200–2000 cycles. The present results clearly indicate that hollow SnO2 spheres with layered crystalline structures are very attractive materials for energy storage because of their ability to intercalate ions into a wide range of sites.

Insight into the mechanism of photocatalytic degradation of gaseous o-dichlorobenzene over flower-type V2O5 hollow spheres

The flower-type V2O5 hollow microspheres with assistance of carbon-sphere templates were fabricated and applied to photocatalytic degradation of gaseous o-DCB.

Controllable synthesis of Sm2O3 crystallites with the assistance of templates by a hydrothermal–calcination process

Sm2O3 crystallites were controllably synthesized by the hydrothermal–calcination process with the assistance of different templates. The phase compositions, morphologies and optical properties of the as-prepared samples were characterized by X-ray diffraction, scanning electron microscope and ultraviolet–visible spectrophotometer. It is investigated that the influence of different templates on the structural and optical properties of Sm2O3 samples. Results showed that Sm2O3 crystallites with ribbon-like, granular and flake-like morphologies were obtained when NaNO3, trisodium citrate and polyvinyl-pyrrolidone (PVP) were used as template agents. These templates effectively controlled the microstructure and optical properties of the as-prepared samples. The monoclinic phase Sm2O3 crystallites with ribbon-like morphology were prepared by using NaNO3 as the template agent, which energy gap is only 4.827eV.

Fine structural tuning of whereabout and clustering of metal-metal oxide heterostructure for optimal photocatalytic enhancement and stability.

In this work, we demonstrate the fine structural tuning of metal-metal oxide heterostructure with regards to the individual tuning of the various core and shell components from shell thickness to metal core constitution. Furthermore, we deliberately engineered spatially confined and clustered Au nanoparticles in the core of a porous shell structure without the assistance of template or linker. Our findings unambiguously highlight that whilst it is important to incorporate metal nanoparticles into metal oxide for higher photocatalytic performance through enhanced light absorption and charge separation, the "whereabout" and clustering of Au nanoparticles affect the photocatalytic performance. Furthermore, we also prove the enhanced and prolonged catalytic activity of spatially confined metal cores over conventional surface loaded metal particles, which originates from the structural stability and optimized contact interface for heterojunction-induced charge transfer. The present well-controlled synthetic route can offer a facile and valuable way to tune and probe specific structure in relation to nanoscale light-matter manipulation and solar-to-chemical energy conversion studies.

Pure monoclinic La1−xEuxPO4 micro-/nano-structures: Fast synthesis, shape evolution and optical properties

Rare-earth-doped LaPO4 crystals have been attracting considerable interest. In this work, we reported the fast syntheses of LaPO4 and Eu-doped LaPO4 crystals via a simple oil-bath route, employing La(NO3)3 and KH2PO4 as the original reactants, Eu2O3 as the dopant. The reaction was carried out in ethylene glycol system at 120°C for 30min without any assistance of surfactants or templates. X-ray powder diffraction analyses showed that pure monoclinic LaPO4 form was obtained in the system without Eu3+ ions, and the above phase was not changed after integrating Eu3+ ions into LaPO4 matrix. However, electron microscopy observations discovered that the integration of Eu3+ ions into LaPO4 matrix obviously changed the morphology and size of the final La1−xEuxPO4 crystals. With the increase in Eu3+ amount from 0 to 0.35, the shape of the final product varied from homogeneous egg-like nanospheroids, to irregular grains with microscales, and to homogeneous microspheroids. Also, the Eu3+ ion content in La1−xEuxPO4 markedly affected the photoluminescence properties of the final product. When x=0.2, the product exhibited the strongest PL emission.

Egg White Derived Tremella-Like Mesoporous Carbon as Efficient Non-Precious Electrocatalyst for Oxygen Reduction

A cost effective non-precious electrocatalyst derived from egg white and doped with iron for oxygen reduction reaction (ORR) is synthesized by a facile method. With the assistance of SiO2 template, the obtained electrocatalyst exhibits a tremella-like morphology with large surface area. Based on the unique surface morphology and the contribution of Fe and N, the as-prepared non-precious electrocatalyst performs a comparable catalytic activity to the commercial Pt/C for ORR in alkaline media, demonstrating a potential application in fuel cells.

Double-sided tin nanowire arrays for advanced thermal interface materials

This investigation examines a type of thermal interface material (TIM) based on a double-sided array of tin nanowires (NWs) prepared using a hot-pressing approach with the assistance of anodic aluminum oxide templates. The metal based TIM effectively reduces the contact resistance, while the flexible nanowires show excellent mechanical compliance to increase the actual contact area with the mating rough surfaces. The results indicate that the overall thermal contact resistance of the two rough copper surfaces assisted by the tin NW array, can reduce the overall resistance to 29 mm2KW-1 at 0.25 MPa and 20 mm2KW-1 at 1.0 MPa.

A simple precursor spraying route to high purity porous B–C–N ceramics

High purity microporous B–C–N ceramics have been successfully synthesized by precursor spraying route without the assistance of template and any other additives. Scanning electron microscopy (SEM) investigation indicated that the sizes of the pores in the ceramics were ranging from 5 to 20μm. Nitrogen adsorption measurements showed that the products had a surface area of 55m2g−1. X-ray photoelectron spectrometer (XPS) and TEM revealed that the main compositions of the products were graphite and hexagonal B–C–N ternary compound.

Construction and Accuracy Assessment of Patient-Specific Biocompatible Drill Template for Cervical Anterior Transpedicular Screw (ATPS) Insertion: An In Vitro Study

BackgroundWith the properties of three-column fixation and anterior-approach-only procedure, anterior transpedicular screw (ATPS) is ideal for severe multilevel traumatic cervical instabilities. However, the accurate insertion of ATPS remains challenging. Here we constructed a patient-specific biocompatible drill template and evaluated its accuracy in assisting ATPS insertion.MethodsAfter ethical approval, 24 formalin-preserved cervical vertebrae (C2–C7) were CT scanned. 3D reconstruction models of cervical vertebra were obtained with 2-mm-diameter virtual pin tracts at the central pedicles. The 3D models were used for rapid prototyping (RP) printing. A 2-mm-diameter Kirschner wire was then inserted into the pin tract of the RP model before polymethylmethacrylate was used to construct the patient-specific biocompatible drill template. After removal of the anterior soft tissue, a 2-mm-diameter Kirschner wire was inserted into the cervical pedicle with the assistance of drill template. Cadaveric cervical spines with pin tracts were subsequently scanned using the same CT scanner. A 3D reconstruction was performed of the scanned spines to get 3D models of the vertebrae containing the actual pin tracts. The deviations were calculated between 3D models with virtual and actual pin tracts at the middle point of the cervical pedicle. 3D models of 3.5 mm-diameter screws were used in simulated insertion to grade the screw positions.FindingsThe patient-specific biocompatible drill template was constructed to assist ATPS insertion successfully. There were no significant differences between medial/lateral deviations (P = 0.797) or between superior/inferior deviations (P = 0.741). The absolute deviation values were 0.82±0.75 mm and 1.10±0.96 mm in axial and sagittal planes, respectively. In the simulated insertion, the screws in non-critical position were 44/48 (91.7%).ConclusionsThe patient-specific drill template is biocompatible, easy-to-apply and accurate in assisting ATPS insertion. Its clinical applications should be further researched.

Electrochemical synthesis of nanostructured materials for electrochemical energy conversion and storage

Electrochemical synthesis represents a highly efficient method for the fabrication of nanostructured energy materials, and various nanostructures, such as nanorods, nanowires, nanotubes, nanosheets, dendritic nanostructures, and composite nanostructures, can be easily fabricated with advantages of low cost, low synthetic temperature, high purity, simplicity, and environmental friendliness. The electrochemical synthesis, characterization, and application of electrochemical energy nanomaterials have advanced greatly in the past few decades, allowing an increasing understanding of nanostructure-property-performance relationships. Herein, we highlight some recent progress in the electrochemical synthesis of electrochemical energy materials with the assistance of additives and templates in solution or grafted onto metal or conductive polymer supports, with special attention to the effects on surface morphologies, structures and, more importantly, electrochemical performance. The methodology for preparing novel electrochemical energy nanomaterials and their potential applications has been summarized. Finally, we outline our personal perspectives on the electrochemical synthesis and applications of electrochemical energy nanomaterials.

Magnetoceramic nanocrystals from the bulk pyrolysis of novel hyperbranched polyferrocenyl(boro)carbosilanes

We report a novel strategy to synthesize nanostructured magnetoceramics via a direct bulk pyrolysis of hyperbranched polycarbosilanes without any assistance of nanoscaled templates. The hyperbranched polyferrocenyl(boro)carbosilanes (hb-PBCS) were synthesized via a convenient A2+B3 strategy. After the pyrolysis of hb-PBCS under a nitrogen atmosphere at 1100 °C, iron silicide nanocrystal enriched ceramics with a grain size of 20–60 nm were formed. The regular architecture and quite higher ceramic yield of polymeric precursors are superior in retaining iron and silicon that give a possibility to aggregate into regular nanocrystals during the bulk pyrolysis in comparison to their linear counterparts. Furthermore, if the mixed precursor of hb-PBCS with regular architecture and a silylene-diacetylene polymer with high ceramic yield was employed, a hierarchical structure of uniform nanorods with diameters of 20–30 nm and aspect ratios of ∼5 together with microspheres with diameters of 4–8 μm could be obtained under the same pyrolytic conditions. A vibrating sample magnetometer measurement demonstrated that the generated iron silicide nanocrystal enriched ceramics possessed weak ferromagnetism with an ultralow hysteresis loss.

Tunability and stability of gold nanoparticles obtained from chloroauric acid and sodium thiosulfate reaction

In the quest for producing an effective, clinically relevant therapeutic agent, scalability, repeatability, and stability are paramount. In this paper, gold nanoparticles (GNPs) with precisely controlled near-infrared (NIR) absorption are synthesized by a single-step reaction of HAuCl4 and Na2S2O3 without assistance of additional templates, capping reagents, or seeds. The anisotropy in the shape of gold nanoparticles offers high NIR absorption, making it therapeutically relevant. The synthesized products consist of GNPs with different shapes and sizes, including small spherical colloid gold particles and non-spherical gold crystals. The NIR absorption wavelengths and particle size increase with increasing molar ratio of HAuCl4/Na2S2O3. Non-spherical gold particles can be further purified and separated by centrifugation to improve the NIR-absorbing fraction of particles. In-depth studies reveal that GNPs with good structural and optical stability only form in a certain range of the HAuCl4/Na2S2O3 molar ratio, whereas higher molar ratios result in unstable GNPs, which lose their NIR absorption peak due to decomposition and reassembly via Ostwald ripening. Tuning the optical absorption of the gold nanoparticles in the NIR regime via a robust and repeatable method will improve many applications requiring large quantities of desired NIR-absorbing nanoparticles.

Bismuth nanowire growth under low deposition rate and its ohmic contact free of interface damage

High quality bismuth (Bi) nanowire and its ohmic contact free of interface damage are quite desired for its research and application. In this paper, we propose one new way to prepare high-quality single crystal Bi nanowires at a low deposition rate, by magnetron sputtering method without the assistance of template or catalyst. The slow deposition growth mechanism of Bi nanowire is successfully explained by an anisotropic corner crossing effect, which is very different from existing explanations. A novel approach free of interface damage to ohmic contact of Bi nanowire is proposed and its good electrical conductivity is confirmed by I-V characteristic measurement. Our method provides a quick and convenient way to produce high-quality Bi nanowires and construct ohmic contact for desirable devices.

Synthesis of copper(ii) coordination polymers and conversion into CuO nanostructures with good photocatalytic, antibacterial and lithium ion battery performances

Two different nanostructured copper–isonicotinic acid (INA) coordination polymers, Cu(C6H4NO2)2(H2O)4 and [Cu(C6H4NO2)(OH)]H2O have been successfully synthesized under hydrothermal conditions on a large scale without the assistance of surfactants or template. Cu(C6H4NO2)2(H2O)4 has the morphology of 2-dimensional (2D) butterfly-like nanosheet structures, while [Cu(C6H4NO2)(OH)]H2O consists of one-dimensional (1D) nanorods. A possible formation mechanism of the obtained coordination polymer nanostructures is proposed with provision of the crystal structure. After heat treatment, hierarchical CuO butterfly-sheet-like nanostructures and CuO nanotubes were obtained. The photocatalytic and antibacterial studies indicate that the as-obtained CuO samples have great photocatalytic activities for the degradation of Rhodamine B and good bacteriostatic activities. In addition, the electrochemical measurements show that CuO samples exhibit high reversible discharge capacities and stable cyclic performances.

Porous peanut-like Bi2O3–BiVO4 composites with heterojunctions: one-step synthesis and their photocatalytic properties

For the first time, porous peanut-like Bi(2)O(3)-BiVO(4) composites with heterojunctions have been synthesized by a one-step mixed solvothermal method with the assistance of a l-lysine template. A mixture of ethylene glycol (EG) and H(2)O (volume ratio of EG-H(2)O = 3:1) is used as the solvent. Unlike the traditional methods, no concentrated HNO(3) and/or NaOH are involved in diluting Bi and V sources in the adopted approach. The as-synthesized peanut-like samples are rough and porous on the surface and to some extent are interior-hollow. The degradation of methylene blue (MB) is employed to evaluate the photocatalytic activity of the Bi(2)O(3)-BiVO(4) composite. It is observed that the composite performs much better than Bi(2)O(3) and BiVO(4), plausibly due to heterojunctions formed between Bi(2)O(3) and BiVO(4). To investigate the relationship between structure and performance, the as-synthesized samples are characterized by XRD, XPS, SEM, TEM (HRTEM), UV-vis DRS, PL and nitrogen adsorption-desorption methods. Additionally, a possible growth mechanism of this hollow peanut-like structure and the separation process of photogenerated electron-hole pairs on the heterojunctions have been discussed.

Low temperature growth of CuS nanoparticles by reflux condensation method

We report a facile, low-temperature soft solution route to synthesize copper sulfide (CuS) nanomaterials with different morphologies by reflux condensation method. CuS nanomaterials were synthesized without the assistance of additional surfactant or templates, and the influence of key synthetic parameters namely solvent medium and sulfur source on the final structure of CuS was comprehensively investigated. XRD pattern of the synthesized products revealed the formation of hexagonal structure of covellite CuS. SEM analysis showed that the CuS products synthesized in water were ball-like microspheres and the products prepared in ethanol were spherical shaped CuS nanocrystals, but those synthesized in ethylenediamine were flower-like CuS hierarchical network consisting of self-assembled nanoflakes as primary building units. DRS exhibited the characteristics broadband absorption of CuS in near-IR region. The optical band gap of the CuS nanocrystals was in the range between 2.35 eV and 2.81 eV, exhibiting considerable blue shift due to quantum size effects. Electrical resistivity measurements confirmed the semiconducting nature of CuS. On the basis of experimental results, the plausible formation mechanism of different CuS nanostructures was put forward and discussed briefly.