Kai Jiang

Henan Normal University, Henan’an, Guangdong, China

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Publications (14)42.22 Total impact

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    ABSTRACT: Graphene-CdS quantum dots (QDs) hybrid materials were successfully prepared via one-step hydrothermal method. CdS QDs with average size of similar to 6 nm were dispersed on graphene sheets with high coverage through non-covalent bonding. Photocurrent and electrochemical impedance spectroscopy (EIS) results suggested that the best dosage of graphene oxide for graphene-CdS hybrid materials is 0.5% (G0.5-CdS). When G0.5-CdS QDs was used as photoanode materials in non-enzymatic sensor, and the sensor was used to detect glucose and displayed satisfactory analytical performance with good linear range from 0.1 similar to 4 mmol dm(-3) with a detection limit of 7 mu mol dm(-3) at a signal-to-noise ratio of 3. The sensor also possessed high selectivity and durability in trace detection of glucose.
    No preview · Article · Jul 2014 · Electrochimica Acta
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    ABSTRACT: Hierarchical TiO(2) microspheres assembled by nanospindles were prepared via a two-step hydrothermal method. The as-prepared products have uniform diameters of ∼450 nm and surface area of ∼88 m(2) g(-1). The optical investigation evidenced that the photoanode film has a prominent light scattering effect at a wavelength range of 600-800 nm and possesses enhanced dye loading capacity. In addition, the electron recombination and transport dynamic measurements indicated that these hierarchical products could suppress the recombination and improve the diffusion coefficient of the photoelectrons, which can be attributed to the improvement of the connectivity by bridging the neighbouring microspheres through the embedded nanospindles. As a result, a high power conversion efficiency of 8.5% was demonstrated, indicating a ∼30% improvement compared with the cell derived from the well-defined nanocrystalline microspheres (6.5%).
    No preview · Article · Nov 2012 · Nanoscale
  • Fang Xu · Yang Bai · Kai Jiang · Li-jie Qiao
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    ABSTRACT: A Y-type hexaferrite rod with the composition of Ba2Co1.8Cu0.2Fe12O22 was presented as an absorbing material with high absorbance. Its high absorbance and wide absorption band result from ferromagnetic resonance (FMR) that is self-biased by strong shape and magnetocrystalline anisotropy fields. Around the FMR frequency the specimen of the ferrite rods exhibits very high absorbance and the FMR frequency can be tuned by the rod dimension. In addition to the high absorbance and the wide tunable absorption band, the microwave absorber has another advantage of light weight due to the use of the ferrite rods instead of ferrite slabs.
    No preview · Article · May 2012 · International Journal of Minerals Metallurgy and Materials
  • Fang Xu · Yang Bai · Kai Jiang · Li-jie Qiao
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    ABSTRACT: The electromagnetic properties of Ba2Co1.8Cu0.2Fe12O22 (Co2Y) and Ba3Co2Fe23.4Zn0.6O41 (Co2Z) were studied by measuring microwave scattering parameters. In the transmission spectra of Ba2Co1.8Cu0.2Fe12O22, a forbidden band emerges due to ferromagnetic resonance, and the permeability will turn to negative in the vicinity of the ferromagnetic resonance frequency. In the complex permittivity spectra of Ba3Co2Fe23.4Zn0.6O41, the negative permittivity can be obtained due to dielectric resonance. Therefore, Co2Y and Co2Z can be used to construct left-handed materials possessing negative permeability and negative permittivity simultaneously.
    No preview · Article · Dec 2011 · International Journal of Minerals Metallurgy and Materials
  • Dapeng Wu · Yi Jiang · Yafei Yuan · Junshu Wu · Kai Jiang
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    ABSTRACT: ZnO–ZnS heterostructures were fabricated via using ZnO rods as template in different Na2S aqueous solutions. These heterostructures are 5–6 μm in length and formed by coating ZnO rod with a layer of porous ZnS shell comprising primary crystals about 10nm in diameter. Subsequently, intact ZnS polycrystalline tubes were obtained by removing the ZnO cores with 25% (wt) ammonia. The as-prepared products were characterized by scanning electronic microscopy (SEM), transmission electronic microscopy (TEM), X-ray diffraction (XRD), energy-dispersive X-ray analysis (EDX), Fourier transform infrared (FT-IR), and electrochemical impedance spectroscopy (EIS). It was found that the electron transfer between ZnS shell and ZnO core strongly affect the photoluminescence and photocatalytic performances of these heterostructures. The rapid transfer of photo-induced electrons from the ZnS shell to the ZnO core leads to enhanced ultraviolet emission. However, if this correlation was destroyed, then the corresponding heterostructure exhibits improved photocatalytic efficiency due to the reduced volume recombination of the charge carries and the multiple reflection effect. Finally, a model based on band-gap alignment was proposed to elucidate the underlying mechanism of the enhanced UV emission and photocatalytic activity of these unique heterostructures. KeywordsSemiconductor–Heterostructure–Crystal growth–Photoluminescence–Photocatalysis
    No preview · Article · Jul 2011 · Journal of Nanoparticle Research
  • Zhiyong Gao · Ying Xiao · Dapeng Wu · Kai Jiang · Fang Xu · Yafei Yuan
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    ABSTRACT: Nano-sized GdPO<sub>4</sub>:Eu<sup>3+</sup> hierarchical hollow spheres were successfully synthesised through chemical conversion using Gd(OH)CO<sub>3</sub>:Eu<sup>3+</sup> nanospheres as templates. The obtained hollow spheres were composed of primary nanowires. Based on the time-dependent experiments, the hollow shells were proposed to be formed through chemical conversion from the precursor spheres. The as-prepared GdPO<sub>4</sub>:Eu<sup>3+</sup> hollow spheres exhibit good photoluminescence performance. Furthermore, the current method can serve as a general way for the synthesis of rare-earth phosphates hollow spheres.
    No preview · Article · Jul 2011 · Micro & Nano Letters
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    ABSTRACT: ZnO materials with different morphologies (hexahedron, coneflowerlike, cauliflowerlike, and nanorods) have been synthesized via a bioinspired method, which is effective and facile for the controlled synthesis of ZnO. Zinc acetate and ammonia were used as growth precursors, and ampicillin was used as the morphology-directing agent. X-ray diffraction (XRD) data showed that the obtained ZnO with different morphologies displayed different crystal growth habits. Photodegradation of Orange G was used as a model reaction to test the photocatalytic activity of ZnO samples. Different morphologies exhibited different activities to Orange G degradation. The cauliflowerlike ZnO sample showed the best photocatalytic performance compared with the others. The influence of the morphology-directing agent and pH on the morphology of ZnO samples and the effect of the morphologies on the photocatalytic activity are tentatively discussed.
    No preview · Article · May 2011 · Canadian Journal of Chemistry
  • Ning Liu · Dapeng Wu · Yi Jiang · Ying Xiao · Yafei Yuan · Kai Jiang
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    ABSTRACT: Monodisperse PbS hollow spheres were successfully prepared via using CdS aggregate spheres as template. The present strategy is based on the different solubilities of CdS and PbS. This process was intensively studied by time-dependent trails which were monitored by transmission electron microscopy (TEM), field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), and photoluminescence spectroscopy (PL). Reaction temperature was found to play an important role in controlling the diffusion rate of Pb2+ ions and the quality of as-prepared PbS crystals, which finally leads to different shape evolution processes from the starting aggregate spheres to the final hollow spheres. Two growth mechanisms defined as kinetics-controlled process (KCP) and thermodynamics-controlled process (TDCP) were, respectively, proposed for the two conversion patterns observed at 30 and 90°C. Moreover, specific structural evolution including primary crystal size, diameter growth, and shell thickness were also discussed in detail. This work is of great significance in elucidating the underlying mechanism of chemical conversion and could be potentially applied to synthesize other hollow architectures.
    No preview · Article · May 2011 · Journal of Materials Science
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    ABSTRACT: Ag/ZnO metal–semiconductor nanocomposites with hierarchical micro/nanostructure have been prepared by the hydrothermal synthesis in the presence of bovine serum albumin (BSA). The results suggest that this biomolecule-assisted hydrothermal method is an efficient route for the fabrication of Ag/ZnO nanocomposites by using BSA both a shape controller and a reducing agent of Ag+ ions. Moreover, Ag nanoparticles on the ZnO act as electron sinks, improving the separation of photogenerated electrons and holes, increasing the surface hydroxyl contents of ZnO, facilitating trapping the photoinduced electrons and holes to form more active hydroxyl radicals, and thus, enhancing the photocatalytic efficiency of ZnO. This is a good example for the organic combination of green chemistry and functional materials.Graphical AbstractA green strategy is report to construct Ag/ZnO metal–semiconductor nanocomposites with hierarchical micro/nanostructure and enhanced photocatalytic activity.Research highlights► Hierarchical micro/nanostructured Ag/ZnO nanocomposites have been prepared via a green route. ► Ag nanoparticles improve the separation of photogenerated electrons and holes. ► This facilitates trapping the photoinduced electrons and holes to form more hydroxyl radicals. Therefore, it enhances the photocatalytic efficiency of ZnO.
    No preview · Article · Apr 2011 · Journal of Solid State Chemistry
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    ABSTRACT: A size-controlled Zn(OH)(2) template is used as a case study to explain the chemical strategy that can be executed to chemically engineering various nanoscale cavities. Zn(OH)(2) octahedron with 8 vertices and 14 edges is fabricated via a low temperature solution route. The size can be tuned from 1 to 30 μm by changing the reaction conditions. Two methods can be selected for the hollow process without loss of the original shape of Zn(OH)(2) template. Ion-replacement reaction is suitable for fabrication of hollow sulfides based on the solubility difference between Zn(OH)(2) and products. Controlled chemical deposition is utilized to coat an oxide layer on the surface of Zn(OH)(2) template. The abundant hydroxyl groups on Zn(OH)(2) afford strong coordination ability with cations and help to the coating of a shell layer. The rudimental Zn(OH)(2) core is eliminated with ammonia solution. In addition, ZnO-based heterostructures possessing better chemical or physical properties can also be prepared via this unique templating process. Room-temperature photoluminescence spectra of the heterostructures and hollow structures are also shown to study their optical properties.
    Full-text · Article · Nov 2010 · Nanoscale Research Letters
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    ABSTRACT: A new route combining a facile wet-chemical process and spin coating was developed to fabricate a CuI film assembled by hexagonal crystals. Remarkably, such a CuI film displays excellent superhydrophobicity without further modification by low-free-energy materials (thiol or fluoroalkylsilane). The special wettability is attributed to a hierarchical morphology of CuI crystals with two length-scale roughnesses and the nature of the material itself. Importantly, this superhydrophobicity is quite stable and the water contact angle of the as-prepared sample only decreases slightly, even when it is kept in air for about half a year. The superhydrophobicity of the as-prepared CuI powder is a bulk property of the material and not just of its surface, so such a powder coating could then prove useful in conferring superhydrophobicity to other surfaces to which it is applied. These facts might improve its practical application with environmental friendship in superhydrophobic coatings.
    Full-text · Article · Sep 2009 · ACS Applied Materials & Interfaces
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    ABSTRACT: Engineering hierarchical CuO hollow micro/nanostructures was realized by a tyrosine-assisted green strategy. The morphology, composition, and phase structure of as-prepared powders were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS), which showed that the sample was assembled from CuO nanosheets with average diameter of ca. 250 nm, self-wrapping to form hollow interiors with an outer diameter of 1.5−3 μm. The improved electrochemical performance toward Li uptake-release verifies their potential application as anode materials in lithium-ion batteries, which attributes to a three-dimensional current collector network and a chemical/mechanical robustness buffer of the as-formed novel CuO structure.
    No preview · Article · Nov 2008 · The Journal of Physical Chemistry C
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    ABSTRACT: Magnetite nanoparticles were fabricated using a biopolymer (sodium alginate)-assisted route via redox-based hydrothermal method using FeCl3·6H2O and urea as the starting materials. The morphology, composition, and phase structure of as-prepared powders were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The results show that biopolymer plays dual roles, reduction, and stabilization, in the formation of the products. This method can be easily controlled and is expected to be applicable for the preparation of other metal oxides. The sample demonstrated a typical ferromagnetic behavior from a direct current SQUID magnetometer (Quantum Design MPMS).
    No preview · Article · Jun 2008 · The Journal of Physical Chemistry C
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    ABSTRACT: This paper presents a hydrothermal method for the synthesis and stabilization of gold nanodisks with a preferential growth direction along the (111) plane inside environmentally-besign sodium alginate sol by a one-step strategy without additional reducing agent. This is carried out by transferring a sodium alginate/HAuCl4 aqueous solution into a stainless steel autoclave with a Teflon liner and heating in an oven at 100°C for 30 h. Field emission scanning electron microscopy observation indicates that the gold nanodisks are predominantly hexagonal shape with micrometer-scale in diameter. Transmission electron microscope, selected area electron diffraction, and Xray diffraction analyses show that the gold nanodisks grow preferentially along the Au (111) plane. Some influential factors on the growth of gold nanodisks are discussed. The results suggest that the reactants' concentrations and reaction time are crucial to the formation of gold nanodisks and their growth mechanism is tentatively explained.
    No preview · Article · Apr 2008 · Current Nanoscience