30 August 2014, Volume 45 Issue 16

    

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工艺 技术
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  Performance of conducting polymer nanocomposites Prepared by Chemical Vapor-Phase Polymerization method

  ;;Yajie Yang ;

  . 2014, 45(16): 1-0.

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  A chemical vapor-phase polymerization (VPP) method was employed to prepare conducting composite poly-3,4-ethylenedioxythiophene (PEDOT)/reduced graphene oxide (RGO) film. The samples to be covered with PEDOT are initially coated with a thin layer of oxidant/GO, and this modifying films was transferred to a VPP chamber containing 3,4-ethylenedioxythiophene monomer gas for chemical polymerization. The latter formed PEDOT/GO film was then treated by glucose and highly conductive PEDOT/RGO films was obtained. The conducive results showed that PEDOT/RGO films exhibited conductivity ca. 35.3 S/cm, which higher than pure PEDOT (17.3 S/cm) and PEDOT/GO (14.6 S/cm) films. The PEDOT/RGO films showed specific capacitance ca. 176.7F/g and kept 84% initial capacitance after 800 cycles, indicating excellent specific capacitance and cycling stability performance. This VPP PEDOT nanocomposites show promising application in supercapacitor and conducting materials.
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  Preparation and Thermoelectric Properties of Mg2Si fabricated by One-Step Synthesis Method

  ;Meng qing sen

  . 2014, 45(16): 2-0.

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  High-purity Magnesium hydride(MgH2),Silicon(Si) and Bismuth(Bi) powders were selected as the raw materials to prepare Bi (1at％)-doped Mg2Si thermoelectric materials by Field-Activated and Pressure-Assisted Synthesis（FAPAS) in one step. The synthesis process, phase component and thermoelectric properties were studied, and the results was also compared with that prepared from tube furnace process followed by FAPAS (T+F).The results shows that it’s feasible to prepare Mg2Si pellet with high purity, nano-structure and also lower thermal conductivity in short time in one-step method, which improves the figure of merit greatly. Meanwhile, a little bit extra silicon particle is helpful to improve the thermoelectric performance of materials，so the sample with a ratio of 1.95:1 has higher ZT value than that of 2:1. At 725K, ZT value of the former reaches 0.54.
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  Preparation of fiber reinforced composite silica aerogel

  ;;Mu YANG ;;;;

  . 2014, 45(16): 3-0.

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  Silica aerogel is a light porous material, and it owns excellent thermal insulating property. Monolithic bulk of silica aerogel composite with high pure glass fiber were prepared through controlling the gelation time during sol-gel process, and drying in ambient pressure/ supercritical pressure. The composite material owns better mechanical properties than pure silica aerogel. Then as-prepared samples are analyzed and characterized by X-Ray diffraction (XRD), nitrogen adsorption (BET), mercury intrusion method (MIP), field emission scanning electron microscopy (FESEM) and thermo analysis. The results show that fiber reinforced aerogels won good mechanical properties, while retain high surface area, low density and low thermal conductivity.
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  The effect of coarsening process on the properties of electroless nickel plating on the surface of lead zirconate titanate ceramic

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  . 2014, 45(16): 4-0.

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  The coarsening process, as the one link in the pretreatment of electroless nickel plating, is extremely vital to the electroless nickel plating process. In order to identify the suitable coarsening way for the lead zirconate titanate (PZT) ceramics, the effect of the roughening process on the deposition performance was studied. In this paper, the PZT ceramics were used as substrate, subjected to rough by five coarsening methods. Ultimately, the nickel deposition on the surface of the PZT ceramics was obtained from alkaline electroless nickel plating solutions at low temperature. A direct comparison between the five types of rough solutions was presented by the analysis of coating appearance test(integrity, uniform, brightness), adhesion force, deposition rate, the corrosion resistance, scanning electron microscopy(SEM) and X-ray diffraction technique(XRD), and the most effective coarsening way for electroless nickel plating on the surface of the PZT ceramics is determined: 30% of the mass fraction of sodium hydroxide, 30 min of roughening time, 30 ℃ of roughening temperature, and the concentration of ethylene diamine is 30 mL/L.
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  Encapsulation of two-phase core materials into electronic ink nanocapsules and the control of the nanocapsules size

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  . 2014, 45(16): 5-0.

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  In this paper, two-phase electronic ink nanocapsules with carbon black nanoparticles modified by SiO2 as dispersant phase and the mixture of tetrachloroethylence and SPAN-80 as dispersant agent were obtained via miniemulsion polymerization. The obtained nanocapsule particle sizes were in the region of about 142~1106nm. We investigated the effects of SiO2 modification on the particle sizes and Zeta potential change of carbon black nanoparticles. Meanwhile, the behaviors of the modified carbon black particles under direct current electric field were also studied. In addition, the influences of the amount of SDS and PVA on the particle sizes of nanocapsules were investigated, respectively.
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  Synthesis of Ultra-thin HfO2 Nano-films by Pure Water-based Sol-Gel Method

  Qing LI;; ;;

  . 2014, 45(16): 6-0.

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  To meet the stringent demands of increasing capacitance density for various devices on microelectronic IC chips, it is necessary to develop new controllable techniques to deposit ultra-thin HfO2 high-k dielectric films with a thickness less than 10 nm. In this work, HfOCl2, HNO3, and H2O2 were used as main raw materials to prepare pure water-based solution precursor diluted with water. HfO2 films were produced via spin-coating on silicon substrate cleaned with plasma. Film thickness, surface morphology and composition were investigated using X-ray reflectivity, AFM and XPS. The results show that this unique Sol-gel approach enables convenient prepa-ration of smooth, dense, and stoichiometric HfO2 nano-films with a growth rate less than 1 nm/cycle.
综述 进展
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  Research Progress in Titanium Dioxide Photo-anode of Dye-sensitized Solar Cells

  . 2014, 45(16): 7-0.

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  The research progress and problems of photo-anode of dye-sensitized solar cells (DSSC) are reviewed in this paper, the methods to improve the performance of DSSC are summarized, and also its prospective development direction is put forward.
工艺 技术
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  Preparation and spectral characteristics of polycrystalline powders of CoTeMoO6

  Xu-Po LIU ;jin cheng guo

  . 2014, 45(16): 8-0.

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  Polycrystalline powders of CoTeMoO6 were prepared via solid reaction method in this paper. The phase composition and microstructure morphology of samples of CoTeMoO6 under different temperature systems were studied, as well as IR and UV-vis spectra. The results show that when the sintering temperature rises to 540-560℃, single phase of CoTeMoO6 with good crystallinity and high purity can be got. The powders of pure phase being sintering at temperature of 600℃, preferential growth of microcrystalline along the crystal plane of (001) occurs and a set of parallel lines of cleavage are observed. With characteristics of a broad transmitting range and high transparency in mid-infrared region, CoTeMoO6 can be served as a kind of potential optical materials. A absorption band of CoTeMoO6 in visible region(450-650nm) appears, which may be caused by the d-d transition of outer shell electrons of Co2+.
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  Preparation of cationic PVA fibers with reaction activity and Its strengthening mechanism

  ;Yi-ding SHEN ;

  . 2014, 45(16): 9-0.

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  Cationic polyvinyl alcohol (PVA) fibers with reaction activity were synthesized via suspension grafting multi-copolymerization using methacryloyloxy ethyl trimethyl ammonium chloride (DMC) and glycidyl methacrylate (GMA) as functional monomers. The influence of DMC and GMA content, concentration of CAN and H+ on grafting rate (GR) of PVA fiber together with the influence of DMC and GMA content on paper strength was discussed. The results show that the desired condition for a better strength of paper is as follow: m (DMC) was 2g, the concentration of CAN and H+ is 8×10-3mol/L and 0.1mol/L respectively. At this time, GR is 15.6%, folding endurance is 241 times, dry tensile strength is 83.10N, wet tensile strength is 30.40N, wet strength is 36.58%. FT-IR and X-ray energy spectrum (EDX) indicate that the grafting copolymerization of GMA and DMC took place on the surface of PVA fiber. SEM photographs show that when m（DMC）/m（GMA）was 2:3, it formed irregular protrusions arranged longitudinally on the surface of modified PVA fiber.
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  Use of H3PO4-loaded waste sawdust for shaping powdery active carbon into monoliths without decreasing specific surface area

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  . 2014, 45(16): 10-0.

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  H3PO4-loaded waste sawdust was used as a binder for shaping a powdered active carbon (PAC) into active carbon monoliths (ACMs). The effects of activation time on the morphologies, microcrystal structures, specific surface areas (SSAs), pore structures, and compression strengths of the ACMs were investigated using SEM, XRD, N2 adsorption-desorption technique and compression test. The H3PO4-loaded waste sawdust was an easy-making binder. Moreover, by using it, the PAC was converted into ACMs without reducing its SSA. An ACM with a SSA of 710m2/g and compression strength of 4.2MPa could be produced by activation at 560℃for 100min using the PAC dosage of 40%. The increase in activation time increased the SSA, micropore volume, and compression strength of ACMs, but hardly affected their microcrystal structure.
研究 开发
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  　　　The supercapacitor properties of carbon nanotubes in hydroquinone/H2SO4 electrolyte

  ;;;;;Enhui Liu

  . 2014, 45(16): 11-0.

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  Actived carbon nanotubes are prepared by carbonizing and activating polyaniline nanotubes, which are synthesized by polymerization of aniline with a template-free self-assembly method in aqueous media. The morphology and surface area of the activated carbon nanotubes were investigated by scanning electron microscopy, transmission electron microscopy and Brunauer-Emmett-Teller measurement (BET), respectively. The electrochemical properties of the supercapacitor in H2SO4 and hydroquinone/H2SO4 electrolyte were evaluated by cyclic voltammetry (CV), galvanostatic charge-discharge (GCD), and electrochemical impedance spectroscopy (EIS) techniques. It was found that the supercapacitor exhibited an outstanding specific capacitance value of 380 F g-1 in the HQ/H2SO4 electrolyte at a sweep rate of 2 mV s-1, which was significantly higher than that of the original supercapacitor (188 F g-1) using 1 M H2SO4 as electrolyte. The result showed that the capacitance of the as-prepared materials was heightened by 192 F g-1, reaching 380 F g-1, which is due to the HQ/H2SO4 electrolyte could provide pseudocapacitance.
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  V2O5 doped ZnFe2O4 composite thin film and it`s sensing properties

  Xeringul ARKIN

  . 2014, 45(16): 12-0.

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  The V2O5 doped ZnFe2O4 solution as a sensitive reagent was prepared by sol-gel methods.And the V2O5 doped ZnFe2O4 solution was fabricated through the dip-pulling methods and was coated on to the surface of tin diffused glass optical waveguide,then we obtained the V2O5 doped ZnFe2O4 composied thin film/tin diffused optical waveguide sensor.After fabricating the sensor ,we detected the sensing properties of the gases such as xylene, styrene to the film.The experimental results indicated that this sensor exhibited good sensitivity、repeatability and selective response to xylene.The minimum concentration of detection to xylene of sensor is 1×10-6.The sensor had high sensitivity,fast response, easily fabricated at room temperature and simple structure.
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  First-principles study on thermodynamic properties of electrode material for LiFePO4 lithium-ion cell

  Liu-Bin SONG ;;;

  . 2014, 45(16): 13-0.

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  By using the ultrasoft pseudopotential plane wave method based on the first-principles, combing the generalized gradient approximation (GGA) and PW91 algorithms, the electronic structure and thermodynamic properties of electrode materials (LiFePO4, Li) in lithium-ion cells were calculated. The results show that the structure of the electrode material LiFePO4 was optimized and achieved the most stable state. The calculated results indicated that the unit cell parameters of the electrode material LiFePO4: a=1.0294nm，b=0.5986nm，c=0.4675nm. The thermodynamic parameters of LiFePO4 lithium-ion cells, such as entropy S, enthalpy H and Gibbs free energy G, were calculated by the phonon density of state. The images according to these data were made and the curves into the function expression were fitted. With the ambient temperature increasing entropy S and enthalpy H increased, but Gibbs free energy G decreased. This result complied with the thermodynamic law. So, the micro calculation provided the theoretical guidance about the practical application of lithium ion batteries.
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  Synthesis of thiol-functionalized mesoporous silica and the thermodynamics of the adsorption of Cr2O72-

  ;ma wenhui

  . 2014, 45(16): 14-0.

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  Uisng the silica fume as silica source, CTAB and PEG-6000 as template agent, the MCM-41 mesoporus silica materials were successfully synthesized. 3-Mercaptopropyl trimethoxysilane was introduced into the network of MCM-41 through post-grafting and thiol-functionalized MCM-41 mesoporous silica (SH-MCM-41) was obtained. The SH-MCM-41 was characterized by XRD, N2 adsorption-desorption isotherm, and FTIR. Cr2O72- adsorption characteristics in water solution have been studied in static experiments with the SH-MCM-41 as adsorbent. The influence of solution pH value and initial metal ion concentration was investigated. And the thermodynamics of Cr2O72- adsorption onto SH-MCM-41 was also studied. It is showed that adsorption capacity of Cr2O72- increased with increasing initial metal ion concentration and temperature. And its highest value was 25.5 mg/g at pH 1. Experimental data fitted well to the Langmuir model at all temperatures studied. The thermodynamic equilibrium functions were also determined. ΔG<0, ΔH=14.2 kJ/mol, ΔS>0, so the adsorption was spontaneous, endothermic and entropy increasing.
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  Effect of compatibilizer on properties of PP/TPS blends

  Man XI; ;;

  . 2014, 45(16): 15-0.

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  The thermoplastic starch (TPS) was plasticized with 30 wt% glycerol. One anionic surfactant 2-(palmitoyloxy) malonate disodium salt (C), which was prepared from glycerol, was used for compatibilizer in blends of PP/TPS/C. Their mechanical properties, melting points, crystallization temperatures, thermostability and rheological properties were analyzed. When added C was 2, i.e., the PP/TPS/C (70/30/2) blends showed the best mechanical property and rheological property. In contrast to the blends without C, the tensile strength decreased from 21.3 MPa to 17.8MPa, whereas the elongation at break increased from 9.3% to 19.7%. The mobility of blends was improved obviously, revealed by the decreasing apparent viscosity. Due to the reactions of C-glycerol, C- starch granule and C-PP, the properties of blends were changed.
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  First principle study of the transformation relationship between HfO2 ferroelectric and tetragonal phases

  Fei YE

  . 2014, 45(16): 16-0.

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  The Pca21 orthogonal phase with ferroelectric property and P42/nmc tetragonal phase of HfO2 have been studied using the augmented plane wave within density functional theory in this work．It has been found out that in the case of the crystal structures, both the ferroelectric phase and the tetragonal phase can be regarded as fluorite-related structure, and the deformation of the unit cells during transformation from the tetragonal phase to the ferroelectric phase is less than 3.75%; in the case of the electronic structures, the hybridization of Hf 5d and O 2p, 2s is enhanced by the transformation from the tetragonal phase to the ferroelectric phase, and the electron states shift to lower energy, which lead to a lower lattice energy of the ferroelectric phase. These results have confirmed that the Pca21 orthogonal phase with ferroelectric property is a stable phase, and provided further insight into the transformation relationship between the ferroelectric phase and the tetragonal phase.
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  Preparation and capacitance property of PANI/ Activated carbon fiber cloths composites with ordered microstructure

  . 2014, 45(16): 17-0.

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  Abstract: Activated carbon fiber cloths (ACC)/polyaniline (PANI) composites with ordered structure were controllable prepared by electrochemical polymerization. The morphology, structure and electrochemical performance of the composites were characterized by SEM, FT-IR and electrochemical method, respectively. It was shown that aniline monomers were spontaneously adsorbed onto ACC by hydrogen bond and electrostatic force interaction between aniline and oxygen-containing groups on the ACC surface. The aniline monomers adsorbed on the ACC were electro-polymerized along the surface when electrochemical reaction was initiated; the PANI with different morphologies was obtained by changing electrolyte, current density and current applied method; The composite with ordered structure exhibits the double-layer capacitor as well as faraday pseudocapacitor characteristics. The specific capacitance of the composites at a current density of 1A/g reached 362 F/g, which was 2.5 times of the ACC at the same condition. The product showed a good electrochemical activity and low cost. The technological process is simple and suitable for industrial production.
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  Fabrication and Piezoresistive Property of TPU/MWNTs Oriented Nanofibers

  . 2014, 45(16): 18-0.

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  Electrospinning is applied to produce oriented nanofibers made of thermal-plastic polyurethane(TPU) and multi-walled nanotubes (MWNTs) composites. TPU/MWNTs films are casted to make comparison. The relationship between relative change in resistance and tensile strain is revealed by tensile testing. The test results show that the maximum gauge factor (≈11.4)of fibers is reached when the mass fraction of MWNTs is 1.84% . At the same mass fraction, gauge factor of films is only 2.6.The piezoresistive response of fibers is linear within 8% of tensile strain which is better than that of TPU/MWNTs films.
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  Fabrication of Al/Al coatings compound materials by liquid-solid bonding method and interface bonding mechanism

  Jian-Hua ZHAO

  . 2014, 45(16): 19-0.

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  A new bimetal compound technology was studied, a layer of pure aluminum coatings was coated on the core by electric arc spraying, the liquid aluminum alloy was poured into the mold to achieve the combination between substrate and coatings after the layer was sandblasted, which was used to enhance the combining capacity of coatings. The results show that the metallurgical bonding interface was obtained between substrate and coatings, and there is the phenomenon that aluminum alloy infiltrate into the coatings. From further study, the technology makes the liquid metal wet, infiltrate, melt and diffuse on the surface of coatings, which realizes the metallurgical bonding between substrate and coatings.
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  Synthesis and characterization of water-soluble CdTe quantum dots

  ; ;;;

  . 2014, 45(16): 20-0.

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  Abstract: A novel technology was developed for the synthsis of thioglycolic acid(TGA)-capped CdTe quantum dots(QDs) while sodium tellurite was used as the tellurium source. The influence of the concentration of Cd2+ and Cd2+-TGA precursor holding time in room temperature on the photoluminescence(PL) and fluorescence quantum yield(QY) were systematically investigated. The obtained QDs were characterized by X-ray powder diffraction(XRD) and transmission electron microcopy(TEM). The results show that the CdTe QDs are of zinc-blended crystal structure in a sphere-like shape. The CdTe QDs with maximum quantum yiele of 48.4% with the condition of the Cd2+-TGA precursors were static for 50min in room temperature before backflow and the concentration of Cd2+ was 0.00067mol/L.
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  Study on the effect of single-crystalline black silicon microstructure on its surface reflectance

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  . 2014, 45(16): 21-0.

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  In this study, single-crystalline black silicon microstructures were fabricated by Ag-assisted chemical etching method under different H2O2 concentration, etching temperature and etching time. Besides, the effects of the black silicon microstructures on the surface reflectance were systematically studied. Scanning electron microscope and spectrophotometer were used to observe the microstructures and to test the surface reflectance, respectively. In addition, the relation between the microstructures and reflectance was deeply investigated by using two light-trapping models. Finally, single-crystalline black silicon with average reflectance of 0.98% from 400 nm to 900 nm was obtained by etching in a 7.8 M HF and 0.6 M H2O2 mixed solution for 90 s at 20 ℃ resulting in an etching depth of 900 nm.
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  Effect of PbTiO3 buffer layer on electric properties of 0.7BiFeO3-0.3PbTiO3 thin film

  Hai-Min Li

  . 2014, 45(16): 22-0.

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  Thin films of 0.7BiFeO3-0.3PbTiO3 (BFPT7030),PbTiO3(PT)-BFPT7030（BFPT7030-1、BFPT7030-2） were prepared on LaNiO3/SiO2/Si substrate by sol-gel process. The test results of XRD and AFM show that the thin films were fully crystalized and reveal highly (100) preferred orientation. These thin films demonstrate smooth surface and the root-mean-squares (RMS) are small. The BFPT7030 thin films with PT buffer layer have improvement dielectric and ferroelectric properties from the test results, and the leakage current is less than the BFPT7030 thin film without PT buffer layer. The film of BFPT7030-2 demonstrate the largest remnant polarization of 38μC/cm2.
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  Functional nitrogen-containing Carbon Materials CCPEI Synthesis and adsorption of heavy metal ions

  ;; PING WEI GUANG;

  . 2014, 45(16): 24-0.

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  porous carbons with high percentage of nitrogen functional groups were synthesized by polyethyleneimine with epichlorodydrin and carbonized in nitrogen atmosphere at certain conditions. Their pore structure, graphite crystalline size, and surface morphology were characterized by nitrogen adsorption isotherms at 77K, FT-IR spectra analysis and seanning electron microscopy. It could be seen that CCPEI has a unitary nanopore structure and nitrogen-containing functional group was preserved in crosslinking process. The adsorption capacities for Cu2+, Pd2+, Al3+, Ce3+, La3+ of CCPEI were 63.776mg·g-1, 83.007mg·g-1, 20.713mg·g-1, 37.506mg·g-1, 14.148mg·g-1 due to its developed pore structure and nitrogen-containing chemical groups. Isothermal adsorption data of adsorption capacities for Cu2+ fits the Langmuir equation and the adsorption quantity are also influenced by temperature and pH.
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  Study on the temperature-magnetic stability of 1J50 alloy

  An-Ruo ZHOU;Yilong Ma ;;

  . 2014, 45(16): 26-0.

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  1J50 soft magnetic alloys are usually used for precision magnetic element because of their excellent soft magnetic properties. In order to better achieve the precision control, it is necessary to understand the magnetic properties in a certain temperature range. The variation of magnetic properties as temperature increasing from -70℃ to 170℃ was studied: there is no change in microstructure; Initial permeability increases as increasing temperature, however, maximum permeability increases as decreasing temperature from room temperature to -70℃; Bs, Br, Ku and Hc decrease with increasing temperature.
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  Formation mechanism and photoluminescence property of hollow porous In2O3 nanofibers

  ;Hui-Zhen KEDa-Wei LI;Lei LUO;

  . 2014, 45(16): 28-0.

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  one-dimensional In2O3 nanofibers with hollow porous structure were prepared by electrospinning and thermal treatment. Thermogravimetry (TGA) was used to analyze the quality changes of precursor composite nanofibers during heat treatment process. X-ray diffractometry (XRD) was used to distinguish the crystal structures of products. The changes of functional groups of precursor composite nanofibers and In2O3 nanofibers were analyzed by fourier transform infrared spectroscopy(FT-IR). The morphology and structure of the nanofibers were characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Fianlly, the photoluminescence property of In2O3 was tested by fluorescence spectrophotometer. The experimental results showed that when In(NO3)3?4.5H2O/PVP=30%, the formation of precursor composite nanofibers was favorable, and the products under high calcination temperature still remained fibrous structure, but the diameters of fibers were obviously reduced. In2O3 nanoparticles existing in In2O3 nanofibers all had cubic bixbyite structure. The average particle size was about 27 nm. A strong green photoluminescence with peaks at 505 nm was observed in the In2O3 nanofibers upon excitation at 250 nm at room temperature.
工艺 技术
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  Preparation and photocatalytic properties of F-Zn-codoped nanocrystalline TiO2

  . 2014, 45(16): 29-0.

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  Fluorine and zinc co-doped nanocrystalline TiO2 were prepared by the sol-gel method and investigated by X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and ultraviolet-visible (UV-Vis) diffuse reflectance spectroscopy, respectively. The photocatalytic performances of the samples were evaluated by photocatalytic degrading methylene blue. The XRD and TEM results show that all the samples are compose of the anatase phase and the average grain sizes are about 16 nm. After the dopings, the absorption properties of the samples can not be obviously enhanced, but the photocatalytic properties of the samples are all improved. The introduction of F- is beneficial to formation of hydroxyl radicals, resulting in the obvious photocatalytic activity enhancement of the sample. With the increase of Zn doping level, the photocatalytic activities of the codoped samples increase and then decrease, gradually. The best photocatalytic property is presented in the codoped sample with 2% Zn doping level.
研究 开发
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  Preparation and corrosion resistance research of Co2+ doping Polyaniline composite film by electrochemical method

  ;Jun-Xia ZHUANG;;;

  . 2014, 45(16): 30-0.

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  Abstract: PANI/Co2+ composite film was synthesized on a stainless steel substrate by cyclic voltammetry (CV) in the solution containing aniline, nitric acid and cobalt nitrate. The structure of the composite film was characterized by Fourier transform infrared (FT-IR), X-ray diffraction (XRD). The corrosion resistance of composite films were investigated by electrochemical testing technologies such as cyclic voltammetry, electrochemical impedance spectroscopy (EIS), Tafel polarization scan in 0.5mol/L H2SO4 electrolyte. The results suggested the poly-aniline doped with Co2+ had good corrosion resistance and could significantly reduce the corrosion current density. The corrosion potential shifted toward the positive direction. The corrosion resistance of the composite film was influenced by the concentrations of Co2+.
综述 进展
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  Graphene-Bismuth Based Oxide Composite Photocatalytic Materials

  Xiao-Jing ZHANG

  . 2014, 45(16): 31-0.

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  Abstract: Currently, environmental and energy issues become increasingly prominent. TiO2, the representative semiconductor photocatalyst, can use solar energy efficiently and provide possibility to solve such problems in this area. Among the reported photocatalysts, bismuth-based oxide with high visible light driven photocatalytic activity attracted widespread attention in recent years. On the other hand, in 2004, graphene was found as a new type of two-dimensional carbon nanomaterials and has been attracted more and more attention owing to its unique physical and chemical properties. Utilizing its excellent conductivity and high specific surface area to increase the photocatalytic activities of bismuth-based oxide has been extensively studied. Compared to the ion doping and coupling with other semiconductors, it is possible to avoid the formation of new internal defects (photo-generated electron-hole recombination centers) in bismuth-based oxide. Our review summarized the progress of graphene enhancing photocatalytic properties of bismuth-based oxide, especially the effects of graphene on bismuth-based oxide including graphene enhancing the specific surface area, light absorption, photocurrent of bismuth-based oxide. The optimized ratios between graphene and bismuth-based oxide were required. Moreover, the effects of chemical bands between graphene and bismuth-based oxide on photocatalytic performance were discussed. Finally, the development trend was prospected based on the preparation of graphene/bismuth-based oxide and the effects of chemical bands.
研究 开发
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  Effect of ion exchange on optical properties of borosilicate glass

  wang yanhang

  . 2014, 45(16): 32-0.

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  The effect of ion exchange on optical properties of borosilicate glass was studied by means of EPMA, spectrophotometer and interference microscope. In the surface of borosilicate glass after ion exchange treatment, content of K+ gradually reduce along the thickness direction. When ion exchange time is less than 8h, thickness of exchange layer increases linearly. However, thickness of exchange layer increases slowly if ion exchange treatment goes on. Transmission of borosilicate glass after ion exchange treatment decreases slightly compared with that of original glass, but it is still higher than 91%. Refractive index of borosilicate glass after ion exchange treatment decreases exponentially from the surface to the inside, which is related with distribution of K+ in borosilicate glass. When ion exchange time is less than 4h, borosilicate glass will possess excellent mechanical and optical properties simultaneously.