Phosphorene is demonstrated to have a great potential in the electronics applications. In this work, the first-principle calculations are employed to predict the mechanical properties and the electronic structure of phosphorene nanosheets and nanotubes. Compared with that of nanosheets, the maximum tensile stress of nanotubes decreases from 17.66 GPa to 11.73 GPa in the zigzag direction and 7.56 GPa to 5.95 GPa in the armchair direction. The ultimate tensile strain of nanosheets is about 27% in the armchair and 25% in the zigzag directions. However, the maximum strain of the zigzag nanotubes decreases to 24% and the ultimate strain of the armchair nanotube is about 14.4%. It presents that the tensile modulus will decrease with the increasing tension, while the compression modulus increases with increasing compression. The results show that zigzag-direction stress will affect the covalent bonds largely, while the armchair-direction stress influences the lone-pair electrons more. Within the allowable strain, the band structure and effective mass of carriers are calculated. The CBM and VBM change their positions when the stress is applied. The effective mass of nanosheets and nanotubes is strongly affected by strain.

The photocatalytic property of TiO2-based nanomaterials can be markedly enhanced by hybridizing conjugated materials at the surface. In this paper, we first utilized a silane coupling agent as carbon source and grafting reagent to prepare a graphite-like carbon coating on the surface of {001} crystal facets that were exposed on TiO2 nanobelts. The thickness of this carbon layer could be controlled to a thickness of a few molecules by adjusting the addition of silane. Due to the synergistic effects between the monolayer carbon coating (~1 nm) and the exposed {001} crystal facets, the as-prepared TiO2 nanobelts enhanced the photocatalytic activity by approximately 2.5 times that of pure TiO2 (Degussa, P–25), to photodegrade methylene blue under UV light. Additionally, the photodegradation of rhodamine B (RHB) was better (approximately 2.1 times) than that of P–25. Further, we discuss the proper mechanism of the enhanced performance, which is attributed to the faster transfer of photogenerated electrons by d-π interaction and the decreased possibility of recombination of e−/h+ pairs.

Poly(o-toluidine) (POT) and p-toluenesulfonic acid doped poly(o-toluidine) (TSA-POT) were synthesized via chemical oxidation and emulsion polymerization, respectively. The rheological measurements of the dedoped POT and TSA-POT silicone oil suspensions showed that both of the suspensions exhibited electrorheological (ER) effect under electric field. The analyses of the rheological curves of suspension indicated that POT and TSA-POT suspensions presented different flow behaviors. POT suspensions presented fast polarization under external electric field with the existence of critical shear rates (γcrit), and POT suspensions behaved well with Bingham model above γcrit TSA-POT suspension behaved very well with Cho–Choi–Jhon model in all shear rate regions. Both of static and dynamic yield stresses for POT and TSA-POT suspensions in electric field were proportional to the square of electric field strength. The different ER performances between POT and TSA-POT suspensions were explained based on the conductivity and dielectric constant of the particles. The modification of conductivity and dielectric constant by doping POT with TSA improved the ER performance of TSA-POT suspension.

As one of the most promising photocatalysts, TiO2 suffers from disadvantages of a wide band gap energy and especially the ultrafast recombination of photoinduced-charges, which limit its practical application for efficient solar water splitting. Here we show a hitherto unreported carbon/TiO2/carbon nanotube (CTCNT) composite featuring a TiO2 nanotube sandwiched between two thin tubes of carbon with graphitic characteristics. The carbon layer is only about 1 nm thick covering the surface of TiO2 nanotubes. The minimum bandgap between the edges of band tails for the CTCNTs can conjecturally be narrowed to 0.88 eV, and the measured apparent quantum efficiency of CTCNT in the ultraviolet light region is even close to 100%, indicating it can greatly enhance the utilization of sunlight and extremely suppress charge recombination. As a consequence, under illumination of one AM 1.5G sunlight, CTCNT can give a super-high solar-driven hydrogen production rate (37.6 mmol h−1 g−1), which is much greater than the best yields ever reported for TiO2-based photocatalysts. We anticipate this work may open up new insights into the architectural design of nanostructured photocatalysts for effective capture and conversion of sunlight.

Li2CoTi3O8 fibers have been synthesized by an electrospinning method and investigated as an anode material for rechargeable lithium-ion batteries. The structure and electrochemical properties of the Li2CoTi3O8 fibers were systematically investigated. Characterization of data collected with high-resolution transmission electron microscopy and scanning electron microscopy reveal that the Li2CoTi3O8 fibers have an average diameter of 300 nm, and the individual fiber is composed of nanoparticles with an average diameter of 48 nm. The nanoparticles not only shorten the distance for Li-ions and electrons to transport but also possess good electrodes electronic contact and high surface area. The results of electrochemical measurements show that the as-prepared Li2CoTi3O8 electrode deliver a specific capacity of 388 mAh g−1 for the first cycle with an irreversible capacity of 156 mAh g−1 and finally remains 237 mAh g−1 after 30 cycles at 50 mA g−1. Its electrochemical performance at subsequent cycles exhibits high cycling capacity and rate capability.Highlights► A simple electrospinning method has been developed to fabricate Li2CoTi3O8 fibers. ► Li2CoTi3O8 fibers as anode material for lithium-ion batteries. ► Li2CoTi3O8 electrode can remain the capacity of 237 mAh g−1 after 30 cycles at 50 mA g−1. ► An irreversible capacity loss of 156 mAh g−1 occurs during the first cycle. ► Li2CoTi3O8 anode exhibits good cycle performance and high rate capability.

Porous lithium titanate (Li4Ti5O12) fibers, composed of interconnected nanoparticles, are synthesized by thermally treating electrospun precursor fibers and utilized as an energy storage material for rechargeable lithium-ion batteries. The material is characterized by X-ray diffraction, scanning electron microscopy, high-resolution transmission electron microscopy, and thermal analysis. Scanning electron microscopy results show that the Li4Ti5O12 fibers calcined at 700 °C have an average diameter of 230 nm. Especially, the individual fiber is composed of nanoparticles with an average diameter of 47.5 nm. Electrochemical properties of the material are evaluated using cyclic voltammetry, galvanostatic cycling, and electrochemical impedance spectroscopy. The results show that as-prepared Li4Ti5O12 exhibits good cycling capacity and rate capability. At the charge–discharge rate of 0.2, 0.5, 1, 2, 10, 20, 40, and 60 C, its discharge capacities are 172.4, 168.2, 163.3, 155.9, 138.7, 123.4, 108.8, and 90.4 mAh g−1, respectively. After 300 cycles at 20 C, it remained at 120.1 mAh g−1. The obtained results thus strongly support that the electrospun Li4Ti5O12 fibers could be one of the most promising candidate anode materials for lithium-ion batteries in electric vehicles.

CoFe2O4/C composite fibers as anode materials for lithium-ion batteries are prepared by thermal annealing of PAN/PMMA/FeAA/CoAA fibers fabricated using the electrospinning technique. X-ray diffraction, scanning electron microscopy, and galvanostatic cell cycling are employed to characterize the structure and electrochemical performance of the as-prepared CoFe2O4/C fibers. SEM images show that the interconnected irregular pores can be found in the fibers. TEM image shows that CoFe2O4 nanoparticles with a diameter of about 42 nm are well dispersed in the carbon matrix. The electrochemical results show that the CoFe2O4/C composite fibers display a stable and reversible capacity of over 490 mAh g− 1 after 700 cycles at a rate of 2.0 C and good rate capability. The experimental results suggest that the CoFe2O4/C fibers synthesized by this method are a promising anode material for high energy-density lithium-ion batteries.Highlights► An electrospinning method has been developed to fabricate CoFe2O4/C fibers. ► CoFe2O4/C fibers with inner porous structure as anode for lithium-ion batteries. ► A stable and reversible capacity of over 490 mAh g–1 after 700 cycles at 2 C. ► CoFe2O4/C anode exhibits good cycle performance and high rate capability.

We carry out the first-principles calculations to investigate the electronic properties of bilayer graphene. The ultrasoft pseudopotential density functional methods within the local density approximation (LDA) are applied. The band structures and density of states of bilayer graphene are investigated. Intrinsic defects, including Stone–Wales (SW) defect and atom vacancy, are considered, and proper theoretical analysis about its electronic properties is given. Finally, we arrive at the point that Stone–Wales defect can generate a small energy gap in bilayer graphene, and the vacancy defect can bring in a magnetic moment of bilayer graphene. The results may be valuable for the application of bilayer graphene in electronic devices.Graphical abstractBand structures of perfect bilayer graphene (a), SW defect (b), spin up (c) and spin down (d) of H-vacancy.Highlights► Effect of intrinsic defects on bilayer graphene is considered. ► Stone–Wales defect can generate a small energy gap in bilayer graphene. ► Vacancy defect can bring in a magnetic moment of bilayer graphene. ► Shift down of Fermi energy was mainly ascribed to the atom around the vacancy.

Polymer electrolytes, based on a blend of poly(methylmethacrylate) [PMMA]/poly(vinylidene difluoride-co-hexafluoropropylene)[P(VdF-HFP)], were prepared by electrospinning at room temperature. The morphology, structure, ionic conduction and mechanical properties of the electrospun membranes were characterized by atomic force microscopy (AFM), FTIR spectra, X-ray diffraction (XRD), electrochemical impedance spectroscopy (EIS) and mechanical measurements. The composites showed the ionic conduction and uptake and leakage behaviors of the electrolyte solution were improved by the addition of PMMA. Also, the mechanical property of the blend membranes was better than that of the pure P(VdF-HFP) electrospun membranes.

Uniform Ag nanowires were successfully synthesized by electrochemical deposition using porous anode aluminum oxide (AAO) as template. The morphology of the AAO and the crystal structure of the Ag nanowires were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD). Nanoscale three-point bending tests performed on an atomic force microscopy (AFM) with picoforce were used to evaluate the mechanical property of a single Ag nanowire. The results showed the elastic modulus ranged from 15.4 to 24.6 GPa as the nanowire diameter of 45.6–60.4 nm.

SiO2 nanoparticles reinforced nylon-6 nanofibers were prepared by electrospinning of nylon-6/SiO2 solution in formic acid. The effect of concentration and applied voltage on the diameter of the fibers was investigated. A nanoscale three-point bending test was used to evaluate the mechanical property of a single nylon-6/SiO2 nanofiber. It was found that the elastic modulus of the nanofibers decreased with the increase in fiber diameter. This elastic modulus was in the range of 3.1–6.9GPa as the diameter ranged from 600 to 100nm.

Poly(vinylidene difluoride-co-hexafluoropropylene) [P(VDF-HFP)] membranes as separators for lithium-ion batteries were prepared from electrospinning. The morphological evolution of the separators at various temperatures were characterized by atomic force microscopy (AFM) equipped with a hot stage. We found the swollen effect of electrolytes on the P(VDF-HFP) phase through in situ observation. The electrochemical measurements results showed the ionic conductivity increased gradually with the increase of temperature. To evaluate the mechanical properties of the P(VDF-HFP) membranes at various temperatures, the tensile curves of the separators were also investigated.

Ag nanowires as electrode materials were prepared from modified anodic aluminum oxide (AAO) template method by using dextrose as reductive, and the process of Ag nanowires growth was monitored by atomic force microscopy (AFM) and scanning electron microscopy (SEM). The structure and electrochemical properties of Ag nanowires were characterized by X-ray diffraction (XRD), UV–vis absorption spectra and cyclic voltammograms (CV) measurements. The results show that Ag nanowires prepared from AAO possessed typical face centered cubic structure with average diameter of 60 nm. Furthermore, the CV characterization reveals that Ag nanowires featured a pair of asymmetrical redox peaks with the position near 0.5 V and the microstructure was maintained in electrochemical reaction.

LiNi1/3Mn1/3Co1/3O2 nanofibers as cathode materials for lithium ion batteries were prepared from sol–gel precursor by using electrospun method. The morphology of nanofibers mats was investigated by atomic force microscope (AFM). The results show that the diameter of LiNi1/3Mn1/3Co1/3O2 nanofibers was in the range of 100–300 nm and nanofibers retained the original morphology feature of gel fibers after sintering at high temperature. X-ray diffraction (XRD) and charge–discharge experiments were used to characterize its structure and electrochemical properties. The specific capacity of LiNi1/3Mn1/3Co1/3O2 nanofibers reached 162.82 and 135.18 m Ah g−1 at 0.2 and 2.0 C, respectively.

The non-isothermal crystallization kinetics of pure polyamide 6 (PA6) and novel PA6/silica-containing epoxy resin nanocomposites (EPA6N) were extensively studied by differential scanning calorimetry (DSC). Three methods, namely, the Avrami, the Ozawa, and the Mo, were used to describe the non-isothermal crystallization process of pure PA6 and EPA6N. It was found that all these three methods can describe the non-isothermal crystallization of pure PA6 very well, but the Ozawa analysis was rather inapplicable for the EPA6N. The Avrami analysis results show that the crystallization rate of EPA6N is faster than that of pure PA6, and the crystallization mechanism of EPA6N is different from that of pure PA6, in agreement with the Mo analysis results.

A novel polyamide 6/silica nanocomposite containing epoxy resins (EPA6N) was prepared via in situ polymerization using tetraethoxysilane (TEOS) as the precursor of silica. The dynamic rheological properties of pure PA6 and EPA6N at temperatures of 225 and 235 °C were investigated. The results of transmission electron microscopy (TEM) and atomic force microscopy (AFM) indicate that the silica particles are well dispersed in the polyamide 6 matrix on about 30 nm in diameter, which demonstrates that this method can effectively avoid agglomeration of the inorganic particles. The rheological results suggest that pure PA6 shows Newtonian behavior. However, the novel EPA6N exhibits a solid-like rheological behavior, which is due to the small size, large surface of silica particles and the stronger polyamide 6-silica chemical bond formed through the reactions of epoxy resins with end groups of PA6 molecular chains. The EPA6N also exhibits higher melt viscosity, storage modulus and loss modulus than those of pure PA6.

The material of porous nano-TiO2 was prepared with a new preparation method. The relations between the crystalloid and the size of TiO2 nanograin and the technics conditions were studied. The control of TiO2 nanograin was discussed initially. It has very high photocatalytic activity. The degradation rate of the methyl orange solutions (50 mg L−1) which were decomposed by nano-TiO2 in the irradiation of the ultraviolet high-voltage mercury lamp whose main wavelength is 365 nm only in 17 min was above 99.6%. After stopping irradiation, there is a degradation dark-reaction whose reaction rate is rapid at first and then slow down. The standpoint that in the anatase TiO2 there are thimbleful rutile TiO2 which could bring the cooperation photocatalysis degradation and improve its photocatalytic activity was first put forward.

Based on the geometric grid information as geometric coordinates, an algebraic multigrid (AMG) method with the interpolation reproducing the rigid body modes (namely the kernel elements of semi-definite operator arising from linear elasticity) is constructed, and such method is applied to the linear elasticity problems with a traction free boundary condition and crystal problems with free boundary conditions as well. The results of various numerical experiments in two dimensions are presented. It is shown from the numerical results that the constructed AMG method is robust and efficient for such semi-definite problems, and the convergence is uniformly bounded away from one independent of the problem size. Furthermore, the AMG method proposed in this paper has better convergence rate than the commonly used AMG methods. Simultaneously, an AMG method that can preserve the quotient space, which means that if the exact solution of original problem belongs to the quotient space of discrete operator considered, then the numerical solution of AMG method is convergent in the same quotient space, is obtained using the technique of orthogonal decomposition.