1D Nanobelts Research Articles

Ice crystal guided folding of graphene oxides in a confined space: a facile approach to 1D functional graphene structures.

The controlled conformational changes of planar graphene nanosheets are of great importance to the realization of their practical applications. Despite substantial effort in the area, the controlled folding of two-dimensional (2D) graphene sheets into one-dimensional (1D) structures still remains a significant challenge. Here, for the first time, we report an ice crystal guided folding strategy to fabricate 1D folded graphene nanobelts (FGBs), where the formation and growth of ice crystals in a confined space function to guide the folding of 2D graphene oxide (GO) nanosheets into 1D nanobelts (i.e. folded graphene oxide belts, FGOBs), which were subsequently converted to FGBs after annealing. Thin aqueous GO containing films were obtained by blowing air through a GO dispersion in the presence of a surfactant, polyoxypropylenediamine (D400), resulting in a foam containing uniform air bubbles. Subsequent shock cooling of the foam using liquid nitrogen resulted in the facile fabrication of FGOBs. This technique provides a general approach to encapsulate catalytic nanomaterials such as Fe3O4 nanorods, TiO2 and Co3O4 nanoparticles into the folded graphene structure for practical applications such as Li-ion batteries.

Thermolysis-Driven Growth of Vanadium Oxide Nanostructures Revealed by In Situ Transmission Electron Microscopy: Implications for Battery Applications.

Understanding the growth modes of 2D transition-metal oxides through direct observation is of vital importance to tailor these materials to desired structures. Here, we demonstrate thermolysis-driven growth of 2D V2O5 nanostructures via in situ transmission electron microscopy (TEM). Various growth stages in the formation of 2D V2O5 nanostructures through thermal decomposition of a single solid-state NH4VO3 precursor are unveiled during the in situ TEM heating. Growth of orthorhombic V2O5 2D nanosheets and 1D nanobelts is observed in real time. The associated temperature ranges in thermolysis-driven growth of V2O5 nanostructures are optimized through in situ and ex situ heating. Also, the phase transformation of V2O5 to VO2 was revealed in real time by in situ TEM heating. The in situ thermolysis results were reproduced using ex situ heating, which offers opportunities for upscaling the growth of vanadium oxide-based materials. Our findings offer effective, general, and simple pathways to produce versatile 2D V2O5 nanostructures for a range of battery applications.

Light-Induced Wavelength Dependent Self Assembly Process for Targeted Synthesis of Phase Stable 1D Nanobelts and 2D Nanoplatelets of CsPbI3 Perovskites.

Despite black cubic phase α-CsPbI3 nanocrystals having an ideal bandgap of 1.73 eV for optoelectronic applications, the phase transition from α-CsPbI3 to non-perovskite yellow δ-CsPbI3 phase at room temperature remains a major obstacle for commercial applications. Since γ-CsPbI3 is thermodynamically stable with a bandgap of 1.75 eV, which has great potential for photovoltaic applications, herein we report a conceptually new method for the targeted design of phase stable and near unity photoluminescence quantum yield (PLQY) two-dimensional (2D) γ-CsPbI3 nanoplatelets (NPLs) and one-dimensional (1D) γ-CsPbI3 nanobelts (NBs) by wavelength dependent light-induced assembly of CsPbI3 cubic nanocrystals. This article demonstrates for the first time that by varying the excitation wavelengths, one can design air stable desired 2D nanoplatelets or 1D nanobelts selectively. Our experimental finding indicates that 532 nm green light-driven self-assembly produces phase stable and highly luminescent γ-CsPbI3 NBs from CsPbI3 nanocrystals. Moreover, we show that a 670 nm red light-driven self-assembly process produces stable and near unity PLQY γ-CsPbI3 NPLs. Systematic time-dependent microscopy and spectroscopy studies on the morphological evolution indicates that the electromagnetic field of light triggered the desorption of surface ligands from the nanocrystal surface and transformation of crystallographic phase from α to γ. Detached ligands played an important role in determining the morphologies of final structures of NBs and NPLs from nanocrystals via oriented attachment along the [110] direction initially and then the [001] direction. In addition, XRD and fluorescence imaging data indicates that both NBs and NPLs exhibit phase stability for more than 60 days in ambient conditions, whereas the cubic phase α-CsPbI3 nanocrystals are not stable for even 3 days. The reported light driven synthesis provides a simple and versatile approach to obtain phase pure CsPbI3 for possible optoelectronic applications.

A Novel Synthesized 1D Nanobelt-like Cobalt Phosphate Electrode Material for Excellent Supercapacitor Applications.

In the present report, we synthesized highly porous 1D nanobelt-like cobalt phosphate (Co2P2O7) materials using a hydrothermal method for supercapacitor (SC) applications. The physicochemical and electrochemical properties of the synthesized 1D nanobelt-like Co2P2O7 were investigated using X-ray diffraction (XRD), X-ray photoelectron (XPS) spectroscopy, and scanning electron microscopy (SEM). The surface morphology results indicated that the deposition temperatures affected the growth of the 1D nanobelts. The SEM revealed a significant change in morphological results of Co2P2O7 material prepared at 150 °C deposition temperature. The 1D Co2P2O7 nanobelt-like nanostructures provided higher electrochemical properties, because the resulting empty space promotes faster ion transfer and improves cycling stability. Moreover, the electrochemical performance indicates that the 1D nanobelt-like Co2P2O7 electrode deposited at 150 °C deposition temperature shows the maximum specific capacitance (Cs). The Co2P2O7 electrode prepared at a deposition temperature 150 °C provided maximum Cs of 1766 F g-1 at a lower scan rate of 5 mV s-1 in a 1 M KOH electrolyte. In addition, an asymmetric hybrid Co2P2O7//AC supercapacitor device exhibited the highest Cs of 266 F g-1, with an excellent energy density of 83.16 Wh kg-1, and a power density of 9.35 kW kg-1. Additionally, cycling stability results indicate that the 1D nanobelt-like Co2P2O7 material is a better option for the electrochemical energy storage application.

Fabrication of Phosphorus-Doped Cobalt Silicate with Improved Electrochemical Properties.

The development of electrode materials for supercapacitors (SCs) is greatly desired, and this still poses an immense challenge for researchers. Cobalt silicate (Co2SiO4, denoted as CoSi) with a high theoretical capacity is deemed to be one of the sustainable electrode materials for SCs. However, its achieved electrochemical properties are still not satisfying. Herein, the phosphorus (P)-doped cobalt silicate, denoted as PCoSi, is synthesized by a calcining strategy. The PCoSi exhibits 1D nanobelts with a specific surface area of 46 m2∙g−1, and it can significantly improve the electrochemical properties of CoSi. As a supercapacitor’s (SC’s) electrode, the specific capacitance of PCoSi attains 434 F∙g−1 at 0.5 A∙g−1, which is much higher than the value of CoSi (244 F∙g−1 at 0.5 A∙g−1). The synergy between the composition and structure endows PCoSi with attractive electrochemical properties. This work provides a novel strategy to improve the electrochemical performances of transition metal silicates.

Synthesis of self-assembled one-dimensional perovskite nanobelt passivated by homophthalic acid and application in WLED

While there has been extensive investigation of synthesizing perovskite nanocrystals (NCs) in light emitting diode (LED) with high photoluminescence performance and stability, they are still limited by chemical and phase instabilities. Moreover, the protonation occurring between oleic acid (OA) and oleyl amine (OAm), which are common capping ligands to passivate the NCs, promotes the degradation of photoluminescence properties. To overcome these issues, we report a post synthesis passivation strategy for self-assemble CsPbBrI2 1D nanobelt by using bidentate ligand, namely homophthalic acid. The introduced homophthalic acid can passivate the CsPbBrI2 surface defects by reducing exposing Pb2+ to prevent nonradiative recombination. Benefiting from homophthalic acid, the passivated NCs exhibit narrow red photoluminescence at 640 nm with 74 % quantum yield (QY) and remain phase stable after 4 months. The external quantum efficiency (EQE) of the white light emitting diode (WLED) fabricated with QDs passivated with homophthalic acid is 1.99 %, its CIE chromaticity coordinate is (0.31,0.33) and the power efficiency is 2.13 lm/W.

Assembling 1D and Janus Nanobelts into 2D Aeolotropic Conductive Janus Membranes and 3D Double‐Walled Janus Tubes

AbstractTwo‐dimensional (2D) stratified Janus membranes (denoted as SJM) with double aeolotropic electrical conduction and simultaneous magnetism and fluorescence have been designed and constructed via electrospinning by using one‐dimensional (1D) nanobelts and Janus nanobelts as building blocks. The SJM is composed of two layers tightly bonded together. The top layer is a left‐right structured Janus membrane, the left part and right part possess aeolotropic electrical conduction, and the conductive directions are vertical, leading to double aeolotropic conduction. Moreover, red and green fluorescence in the two parts occurs under UV irradiation. The bottom layer is a non‐array magnetic membrane. By rolling the 2D SJM into a tube, either from left to right or top to bottom, three‐dimensional (3D) double‐walled Janus tubes with the Janus tube and the isotropic tube on the exterior and interior of the tube are obtained. The novel 3D double‐walled Janus tubes exhibit the same excellent performance as the 2D SJM. Thus, the structural transition from 1D nanobelts and Janus nanobelts utilized as building units to 2D double aeolotropic conductive Janus membrane then to 3D Janus tube is successfully realized.

Size and morphology dependent gas-sensing selectivity towards acetone vapor based on controlled hematite nano/microstructure (0D to 3D)

Seven 0D-3D α-Fe2O3 nanostructures with different shapes and sizes have been prepared via a solvothermal route and subsequent calcination. It was found that the dosage of hexamethylenetetramine (HMTA) and the kind of solvent played determinant roles in the controlled synthesis of α-Fe2O3 nanostructures. Increasing the amount of HMTA from 0.070 g to 0.420 g, the morphology of α-Fe2O3 product evolves from 1D nanobelt, 2D nanosheet to 3D nanoflower with sizes ranging from 4 μm to 650 nm. Changing the kind of solvent with various chain lengths or polarity, 0D α-Fe2O3 porous nanospheres, rhombohedra and cylinder microstructure can be obtained. Based on the experimental results, the possible formation mechanism of various dimensional products was speculated. The different gas-sensing behaviors that related with the microstructures of the as-prepared α-Fe2O3 samples were also investigated. The fabricated gas sensors all present good stability and high selectivity towards acetone gas, and the comparable responses to acetone should be due to the variation in their size, morphology and specific surface area (SSA). In addition, the gas-sensing conductive mechanism based on the α-Fe2O3 samples was also proposed.

Perforated mesoporous NiO nanostructures for an enhanced pseudocapacitive performance with ultra-high rate capability and high energy density

The morphology of NiO (1D nanobelts and 2D nanosheets) has a significant effect on the pseudocapacitive performance. The perforated and interlinked mesoporous structure of NiO nanobelts delivered higher power and energy density than nanosheets.

Single-Crystalline Nanobelts Composed of Transition Metal Ditellurides.

Following the celebrated discovery of graphene, considerable attention has been directed toward the rich spectrum of properties offered by van der Waals crystals. However, studies have been largely limited to their 2D properties due to lack of 1D structures. Here, the growth of high-yield, single-crystalline 1D nanobelts composed of transition metal ditellurides at low temperatures (T ≤ 500 °C) and in short reaction times (t ≤ 10 min) via the use of tellurium-rich eutectic metal alloys is reported. The synthesized semimetallic 1D products are highly pure, stoichiometric, structurally uniform, and free of defects, resulting in high electrical performances. Furthermore, complete compositional tuning of the ternary ditelluride nanobelts is achieved with suppressed phase separation, applicable to the creation of unprecedented low-dimensional materials/devices. This approach may inspire new growth/fabrication strategies of 1D layered nanostructures, which may offer unique properties that are not available in other materials.

Semiconductive 1D nanobelt iodoplumbate hybrid with high humidity response

Owing to the structural diversity and potential applications in optoelectronic devices, inorganic-organic hybrid materials have attracted extensive attentions in recent years. They are widely used in the fields of fluorescence, photoconductivity, ferroelectricity and solar cells. A new compound, [(Et2)HDABH(Et2)]2Pb5I14·2H2O (DAB = benzidine), was solvothermally synthesized using [(Et2)HDABH(Et2)]2+ as templates and balance cations. The structure is consisted of one-dimensional (1D) nanobelt iodoplumbate, [(Et2)HDABH(Et2)]2+ dications and water molecules. The compound exhibits typical semiconductive behaviors, whose conductivity increases along with the raising of temperature. The compound also shows high electrical response to humidity, which indicates great potential application in humidity quantitatively detecting.

Ionic self-assembly of bundles of ultralong SC/MB nanobelts with enhanced electrocatalytic activity for detection of ascorbic acid

The formation of bundles of ultralong nanobelts by an anion biological surfactant sodium cholate (SC) and a cationic dye (MB) through ionic self-assembly approach was obtained. The nanobelts possess smooth surfaces, flat end facets and solid internal structure. This one dimensional self-assembly is dominated by the π–π stacking interactions between MB molecules in concert with the hydrogen bonding between SC molecules. The shape and length of the bundles of SC/MB nanobelts could be easily controlled by changing the SC concentration and the aging temperature. Moreover, the electrocatalytic properties of the SC/MB nanobelts modified electrode were also investigated and the results indicated that the bundles of ultralong SC/MB nanobelts exhibited efficient electrocatalytic activity towards l-ascorbic acid (AA) in phosphate buffer solution (pH = 7.0). In addition, the electrostatic interaction between AA and MB also facilitates the electrons transfer on the surface of the GCE and promotes the oxidation of AA. The present work provides an alternative way to design and fabricate the ultralong 1D nanobelt structures with tunable sizes using small organic molecules. This system may also open up a way for the design and development of optical and electronic devices in the potential bio-applications and electrocatalyst for fuel cells.

Synthesis of Hierarchical Sisal-Like V2O5 with Exposed Stable {001} Facets as Long Life Cathode Materials for Advanced Lithium-Ion Batteries.

Vanadium pentoxide (V2O5) is considered a promising cathode material for advanced lithium-ion batteries owing to its high specific capacity and low cost. However, the application of V2O5-based electrodes has been hindered because of their inferior conductivity, cycling stability, and power performance. Herein, hierarchical sisal-like V2O5 microstructures consisting of primary one-dimensional (1D) nanobelts with [001] facets orientation growth and rich oxygen vacancies are synthesized through a facile hydrothermal process using polyoxyethylene-20-cetyl-ether as the surface control agent, followed by calcination. The primary 1D nanobelt shortens the transfer path of electrons and ions, and the stable {001} facets could reduce the side reaction at the interface of electrode/electrolyte, simultaneously. Moreover, the formation of low valence state vanadium would generate the oxygen vacancies to facilitate lithium-ion diffusion. As a result, the sisal-like V2O5 manifests excellent electrochemical performances, including high specific capacity (297 mA h g-1 at a current of 0.1 C) and robust cycling performance (capacity fading 0.06% per cycle). This work develops a controllable method to craft the hierarchical sisal-like V2O5 microstructures with excellent high rate and long-term cyclic stability.

Strong efficiency improvement in dye-sensitized solar cells by novel multi-dimensional TiO2 photoelectrode

Titanium dioxide (TiO2) based dye-sensitized solar cells (DSSCs) often exhibit superior power conversion performance. Here we report a DSSC with novel hierarchical TiO2 composite structure (TCS) composed of anatase TiO2 micro-spheres and rutile TiO2 nanobelt framework by hydrothermal approach for high-performance. As photoanode, the TCS based DSSC shows a strong efficiency enhancement by 58% compared with Degussa TiO2 (P25)-DSSC (4.33%). The excellent performance is mainly attribute to its special multi-dimensional structures of TiO2: much active sites of 0D nanoparticle with exposed excellent {001} facet, special electronic transmission channel of 1D nanobelt, good dye adsorption capacity of 2D nanosheet and high light scattering ability of 3D micro-spheres. The novel multi-dimensional TCS materials will open up a new avenue to the electronic devices fields.

One-step synthesis of ultrathin nanobelts-assembled urchin-like anatase TiO2nanostructures for highly efficient photocatalysis

Nanostructured TiO2 materials with a controlled morphology and structure have drawn considerable attention to both fundamental research and practical applications owing to their unique characteristics. Herein, a novel, facile, and one-step hydrothermal approach was developed to synthesize urchin-like anatase TiO2 hierarchical nanostructures assembled from ultrathin nanobelts using urea as the morphology-directing agent. The effects of the urea concentration in the preparation process were discussed intensively. Photocatalytic experiments showed that the urchin-like anatase TiO2 nanostructures possessed a much higher degradation rate of methyl orange and phenol than the most successful commercial semiconductor photocatalyst P25. The reasons for the highly efficient photocatalytic activity was ascribed to the high specific surface area (171 m2 g−1) and ultrathin 1D nanobelts of anatase TiO2 self-assembled into the urchin-like hollow spheres. The urchin-like anatase TiO2 nanostructures as photocatalysts have potential applications in environmental and energy fields for photocatalytic degradation, hydrogen production, Li-ion batteries, and dye-sensitized solar cells. In addition, new hydrothermal method can be developed for synthesis of other hierarchical nanostructures.

Phenanthroline modulated self-assembly of nano/micro-scaled metal–organic frameworks

In stark contrast to the report that phenanthroline is an efficient chelate ligand for lanthanide-based metal–organic framework formation, here it is found that phenanthroline can act as a very useful regent to modulate self-assembly of nano/micro-sized yttrium benzenetricarboxylate (Y–BTC). 1D nanobelts of Y–BTC was firstly produced via a simple, mild one-step approach. Then the morphology was transformed to 3D urchin-like hierarchical architectures with the assistance of phenanthroline. Interestingly, the as-synthesized 3D urchin-like superstructures can be disassembled through simple ultrasonic treatment. Thus a large quantity of 1D nanorods was obtained. Additionally, brilliant-red light of the nanomaterials was realized by doping Eu3+ ions.

Synthesis of three-dimensional (3D) hierarchical titanate nanoarchitectures from Ti particles and their photocatalytic degradation of tetracycline hydrochloride under visible-light irradiation.

Three-dimensional (3D) titanates hierarchical macro/nano-architectures constructed by one-dimensional (1D) nanobelts are successfully synthesized by a hydrothermal-calcining process using metal Ti particles as a precursor. Their morphology and structure are characterized, and their photocatalytic reactivity to tetracycline hydrochloride (TC) is evaluated under visible-light irradiation. The results show that the 1D nanobelts are formed through hydrothermal reaction, and then those 1D nanobelts encircle the metal Ti particles precursor to form 3D macro/nano-architectures. The products with different phase composition, from hydrated titanium oxides to sodium titanates, are obtained by increasing the post-calcining temperatures from 200 degrees C to 800 degrees C. The photocatalytic degradation of TC is observed for all samples under visible-light irradiation, and the sample calcined at 600 degrees C achieves the best photocatalytic reactivity. The visible-light performance of as-synthesized catalysts is considered as a charge-transfer mechanism initiated by the photoexcitation of the surface-complex between TC molecules and titanates, and then followed by the photosensitization mechanism. Two intermediates are identified in the photodegradation process using liquid chromatography combined with mass spectrometry. In addition, the as-synthesized titanates are stable and can be used repeatedly, showing their promising prospect in the practical applications.

Synthesis of nanostructured MgO powders with photoluminescence by plasma-intensified pyrohydrolysis process of bischofite from brine

Abstract Nanostructured MgO powders were synthesized by an ultra-high temperature pyrohydrolysis process of bischofite (MgCl2·6H2 O) in a radio frequency (RF) induction thermal plasma system. The structure, morphology and optical properties were characterized by X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDS), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Raman spectroscopy. The results showed that MgO nanopowders with two different morphologies were fabricated: near spherical MgO nanoparticles with size in the range of 20∼40 nm and 1D nanobelts with a width of about 100 nm. The photoluminescence (PL) studies showed that both of these two kinds of nanostructured MgO powders exhibited a strong ultraviolet-green PL emission under the excitation of 325 nm He-Ne laser.

Cu doped V2O5 flowers as cathode material for high-performance lithium ion batteries

Hierarchical Cu doped vanadium pentoxide (V2O5) flowers were prepared via a simple hydrothermal approach followed by an annealing process. The flower precursors are self-assembled with 1D nanobelts surrounding a central core. The morphological evolution is investigated and a plausible mechanism is proposed. As the cathode material for lithium ion batteries, the Cu doped V2O5 samples exhibit improved electrochemical performance compared to the un-doped ones. Among them Cu0.02V1.98O5 delivered higher reversible specific capacities, better cycling stabilities and excellent rate capabilities, e.g. 97 mA h g(-1) at 20.0 C.

Self-assembly and optical properties of N N′-bis(4-(1-benzylpiperidine))perylene-3,4,9,10-tetracarboxylic diimide

Well-defined nanobelts with strong fluorescence were fabricated from a perylene tetracarboxylic diimide molecule modified with specific side-chain substitution. The new perylene diimide was characterised by 1H, 13C NMR, mass and IR spectral techniques. The photophysical and electrochemical properties were investigated by UV–vis absorption, fluorescence, differential scanning calorimetry and cyclic voltammetry. 1D nanobelt self-assembly of the compound was studied with optical, fluorescence and scanning electron microscopic techniques. The observed self-assembly was supported by computational studies using density functional theory and natural bond order analysis. The optimised molecule was fit into crystal space theoretically, and the observed band gap was correlated well with optical and electrical properties.