30 October 2013, Volume 44 Issue 20

    

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综述 进展
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  Development on High Capacity Layered Mn-Based Oxide Cathode Materials

  Min GAO;Fang LIANCui Jun TIAN;;;

  . 2013, 44(20): 2905-2912.

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  Layered Mn-based oxides Li[Lix(MnM)1-x]O2 (M=Ni, Co, Cr……) have attracted much attention due to their high reversible capacity. In the paper, we review the latest development in these areas, both from our group and others. The structure, synthesis methods and electrochemical properties of Li[Lix(MnM)1-x]O2 are summarized. Especially, the charge/discharge mechanism and improvement to their electrochemical properties are focused here. At last, the major problems in layered Mn-based oxides is discussed.
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  Research progress in biomedical magnesium alloys

  Tao LI;;;;

  . 2013, 44(20): 2913-2918.

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  Due to the excellent mechanical compatibility, biocompatibility and biodegradability, magnesium and its alloys are becoming the research focus of a new generation of biomedical degradable metallic implant materials. However, the rapid degradation rate of magnesium and its alloys puts serious obstacles in the way of their clinical applications. It is highly urgent to develop magnesium alloys with high strength, high toughness, high corrosion resistance, and controllable degradation behavior. The latest research progress in degradable biomedical magnesium alloys is reviewed. The advantages and disadvantages, current products, degradation mechanism and corrosion behavior, and corrosion resistance research are presented in detail for magnesium and its alloys as biomedical materials. The problems in the research and future development directions are also pointed out.
研究 开发
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  Study on Preparation and Property of Doped Conductive Polyaniline(PANI) Base on Grey System Theory

  Hui-Xia FENG ;;Yi WANG

  . 2013, 44(20): 2919-2922.

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  With aniline(An) as monomer, sulfamic acid(SA) as dopant, ammonium persulfate(APS) as oxidant, prepared doped conductive Polyaniline(PANI) via chemical oxidation polymerization. We researched the effect of molar ratio of An and dopant, An and oxidant, and reaction time to the conductivity of PANI. The conductivity of PANI is to 0.87S?cm-1, when reaction time is 6h and n(An)︰n(SA)︰n(APS) =1︰6︰0.4. Furthermore, the extents of factors affecting the conductivity of PANI were analyzed quantitatively using the grey relational analysis with the order of the dopant,oxidant,reaction time.And basing on grey prediction theory, the grey discrete Verhulst model of the conductivity of PANI was built with the sulfamic acid(SA) addition as base quantity by dealing with the original experiment data. The conductivity of PANI was predicted at the different sulfamic acid(SA) addition.The average accuracy is 97.25%.The application examples show that these new methods have higher accuracy , therefore the conductivity of PANI forecasting based on grey system theory is feasible.．
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  Effect of cerium concentration on the antifouling of electroless Ni-P-PTFE composite coatings

  Xu He;FU Chuan Qi ;;WANG Zhou

  . 2013, 44(20): 2923-2926.

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  Rare earth cerium (Ce) promoting Ni-P-PTFE composite coatings were prepared on 45# carbon steels specimens by Electroless deposition. The surface morphology of the coatings was analyzed by scanning electron microscope (SEM), effect of Ce concentration in the plating bath on deposition rates, PTFE content and fouling rates of the composite coatings were also investigated. The results indicate that addition of Ce into the bath significantly increases the black particles in the SEM pictures which indicates that the PTFE content of the coatings increases. As increase of Ce concentration in the plating bath, the deposition rates and the PTFE content of the coatings increases firstly, and reaches the maximums of 28.25μm?h-1 and 40.43%% in the Ce concentration of 0.04g/l, respectively, then gradually decreases. And PTFE content of the coatings increases with the increase of the deposition rates. In addition, addition of Ce in the plating bath improves the antifouling property of the coatings, and the fouling rates relate to the PTFE content of the coating which changes with the Ce concentration and decreases to 9.026g?m-2 in the Ce concentration of 0.04g/L.
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  Properties of W-Cu composite powders synthesized by Sol- Ball Milling

  . 2013, 44(20): 2927-2930.

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  In this study, W-10Cu/W-20Cu composite powders were fabricated by sol-spray drying and ball milling. The particle sizes and morphology of the composite powders were tested, the densification behave was studied. The results show that a new peak appeared after milling. After 20 hours ball milling, particle sizes of W-10Cu/W-20Cu were 1.03 and 1.15μm, respectively. The derivation of specific surface area ln(Sm-S0/Sm-S) and milling time t match liner relationship. When sintered directly at 1380℃ after 20h milling, W-10Cu/W-20Cu composites had a uniform composition distribution and fine grain sizes, which approached to full density.
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  Photonic Band Gap Effects upon Energy Transfer in Luminophors

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  . 2013, 44(20): 2931-2935.

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  Research on structure and properties of copper-based nano Al2O3 composite coating prepared with electro-brush plating

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  . 2013, 44(20): 2936-2939.

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  Abstract：Traditional Cu coating and Cu/nano-Al2O3 composite coating were prepared respectively with electro-brush plating on pure copper matrix. The surface morphology, section structure, micro-hardness and wear resistance of both coatings were determined and comparatively analyzed with canning electron microscope, metallographic microscope, digital micro-hardness tester and friction-wear tester. The results showed that, the structure, morphology and properties of Cu/nano-Al2O3 composite coating are changed due to adding nano-Al2O3 particles to the Cu based coating. The surface morphology of Cu/nano-Al2O3 composite coating is more leveling and smooth, the microstructure is more compact, micro-hardness is higher and friction coefficient is lower than that of traditional Cu coating. Cu/nano-Al2O3 coating has strong resistance effects on plough and adhesion wear. The wear resistance of Cu/nano-Al2O3 composite coating is superior to that of traditional Cu coating.
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  The preparation and the wettability study of the copper nano-structure surface

  . 2013, 44(20): 2940-2944.

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  We prepared a superhydriphilic film on copper by a facile Hydrothermal method, the water contact angle is 6°. After modified with Fluoride, the surface exhibits superhydrophobicity and the water contact angle can reach 156°, the sliding angle less than 10 o. The result of the XRD patterns confirms that the nano-structure is cupric oxide. The SEM shows that the morphology rely on the temperature and reaction time. The airs among the nano structures and the Fluoride lead to the superhydrophobicity. when the film was put down the water with varies height, the superhydrohobicity is changed even to a superhydrophilicity. The reason of the change is discussed briefly.
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  Influence of polyvinylpyrrolidone on morphology and dispersity of magnesium hydroxide

  ;Du Fang lin;

  . 2013, 44(20): 2945-2948.

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  Magnesium hydroxide of sheet-, flower-, sphere-, rod- and belt-like morphologies were prepared at ambient conditions via ammonia method with the help of polyvinylpyrrolidone (PVP). The morphology, dispersity and crystallinity of the as-prepared magnesium hydroxide were investigated by means of SEM, TEM and XRD. The results show that a facile method of controllable continuous synthesis of magnesium hydroxide was developed with the help of PVP, in which the products were fabricated with different morphology and good dispersity.
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  The research on the base material of Chitosan /Polyacrylamide Hydrogel

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  . 2013, 44(20): 2949-2953.

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  Abstract: Preparing a new type of hardness variable biological substrate material. Using these experiments of infrared spectroscopy, water absorption of weighing , the rotational rheometer, and MTT to measure the structure, the swellable, elastic modulus, and cytotoxicity.of chitosan / polyacrylamide hydrogel HepG2 cells were inoculated into the mixed hydrogel base material of Chitosan / Polyacrylamide, and after 24 hours giving a morphological observation the cells grown on the material. The hardness of the different formulation of Chitosan /Polyacrylamide Hydrogel has obvious gradient differences and has a good biocompatibility. This new type of the biological substrate material can provide research for the basic of cell mechanics.
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  Effects of oxidative modification of carbon surface on selective removal of nitrogen compounds from model fuel

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  . 2013, 44(20): 2954-2958.

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  This work examines the adsorptive selectivity of activated carbon (AC) MSC-30 for the nitrogen compounds, quinoline, indole and carbazole, based on aromatic naphthalene as reference compound. Furthermore, the effects of three different oxidation modification methods on the adsorptive selectivity of AC were investigated. It was found that both of original and modified ACs selectively adsorbed nitrogen compounds. Oxidation modification of AC further improved the selectivity for nitrogen compounds as well as the adsorption capacity of nitrogen compounds. The frontier orbital distribution of target adsorbates was calculated through the density functional theory (DFT) method. The results demonstrated that the higher selectivity for nitrogen compounds than that for aromatic naphthalene was consistent with the order of adsorbates' reaction activities. Moreover, due to the increased surface oxygen-containing groups on oxidized activated carbon, they weren’t beneficial to adsorb stable naphthalene, but favored adsorbing indoles and quinoline, especially tended to adsorb basic quinoline. The adsorptive capacity for quinoline on severely oxidized samples MSC-N and MSC-NS could reach 1.05mmol.g-1 and 1.06mmol.g-1, respectively.
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  Properties of Variable Emissivity Thermal Control Coatings

  . 2013, 44(20): 2959-2962.

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  Perovskite structure manganese oxide thermal control coatings were synthesized by solid-state reaction method. The relationship between the total hemispherical emittance (εH) and the temperature of the thermal control coatings was measured on a calorimetric emissometer which was based on the steady state calorimetric method. The compounds show thermochromic properties and εH have low value at low temperature and have high value at high temperature. Environmental adaptability tests such as ultraviolet irradiation test, proton irradiation test, electron irradiation test, thermal cycle test, outgassing test were made also, the test results show that thermal control coatings has very good space stability performance, which make the thermal control coatings attractive as potential active thermal control materials for future satellites.
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  Microwave absorbing property of magnetic polyphosphazene nanotubes carbonized at high temperature

  Xiao-Yan ZHANG

  . 2013, 44(20): 2963-2966.

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  Novel microwave absorbing carbon based composites were prepared by carbonizing magnetic polyphosphazene nanotubes at high temperature in an inert atmosphere. The magnetic responsivity was studied in the magnetic field and the resistivity was measured by four-probe method. The electromagnetic parameters were measured by using coaxial transmission and reflection way and the microwave absorbing properties were studied. The results showed that the composites oriented in the magnetic direction, exhibiting good magnetic responsivity. The composites are semiconductors with resistivity of 7.88 (Ω?cm). In the frequency range of 2-18 GHz, there are both dielectric loss and magnetic loss. The maximum reflection loss is -14 dB at 14 GHz and the composites showed certain wide-frequency properties.
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  The Investigation of Carbon Supported Pt-P/C Catalyst for the Oxidation of Methanol

  Gai-xiu YANG ;;;;

  . 2013, 44(20): 2967-2970.

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  The influence of substitution degree on the structure and properties of carboxymethyl viscose nonwoven

  xianxin xi;;;;Ping ZHU

  . 2013, 44(20): 2971-2975.

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  Carboxymethyl viscose nonwoven (CM-VN) has been successfully prepared in aqueous medium through one bath process. The structure of fiber in CM-VN was studied by XRD and SEM. And the influence of substitution degree (DS) on the hygroscopicities, water vapor permeabilities, water diffusion properties and mechanical properties of CM-VNs was investigated. The results showed that, with increasing DS of CM-VN, its crystallinity degree decreased gradually, hygroscopicity enhanced remarkably, water vapor permeability and water diffusion property decreased smoothly, however, breaking strength first increased then decreased. With DS of 0.35, CM-VN could form uniform and semitransparent hydrogel after absorbing water. And its water absorption reached 25.44 g?g-1 (distilled water) and 24.38 g?g-1 (normal saline), breaking strength and breaking elongation were respectively 85.7 N and 47.5%. In addition, it has good water vapor permeability and blocking performance. Therefore, CM-VN could be used as absorbing material for the preparation of high performance medical dressings.
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  Preparation and properties of tetraethylenepentamine phosphonic chelating fiber

  ;;Li Mingyu

  . 2013, 44(20): 2976-2980.

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  Tetraethylenepentamine phosphonic chelating fiber (TEPAPCF) was successfully prepared after acylation, amination and methyl phosphorylation of propylene fiber grafted with styreneylbenzene(PP-g-ST). The reaction conditions of methyl phosphorylation were optimized by the way of L16 (45) orthogonal test. The best adsorption capacity of Cu2+ on TEPAPCF was 2.20 mmol?g-1. SEM, photoelectron spectroscopy (EDX), IR, TG, XRD and mechanical strength test were used to invertigate the structure and propties of TEPAPCF. The result of adsorption performance test shows that TEPAPCF has good adsorption selectivity to Fe3+ and In3+, and greater adsorption ability of Fe2+ and Fe3+ than the resin with similar structure.
工艺 技术
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  Preparation of Silicon Nitride Fibers by Pyrolysis Nitridation of Polycarbosilance

  Lin LAN ; ;;An-Hua LIU

  . 2013, 44(20): 2981-2984.

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  In this work, PCS cured fibers were pyrolysis nitridation in the ammonia atmosphere for carbon removal and amination, and then condensation/nitridation reaction at high temperature in the nitrogen to produce Si3N4 fibers. Results showed that as-prepared Si3N4 fibers were colorless and transparent. What is more, the skin of the fiber was smooth and the cross section was rather dense without identifiable defects. This paper also discussed the mechanism of nitridation and the influence of pyrolysis conditions on the structure and properties of Si3N4 fibers. The results of FTIR spectra and elemental analysis showed that the carbon content was extremely low after amination and pyrolysis, which was less than 1%, while the nitrogen content increased with the elevated pyrolysis temperature, and the oxygen content first increased and then decreased with the elevated pyrolysis temperature. The fibers were amorphous when the pyrolysis temperature was less than 1500℃, while the tensile strength reached a maximum at the temperature of 1300℃. The processes of pyrolysis nitridation were a process of decarburization and ammonification, and then condensation/nitridation at high temperature in the nitrogen, finally producing Si3N4 fibers.
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  Optimization of Processing Conditions of Pennisetum Sinese Roxb Cellulose Nanocrystalline Using Response Surface Methodology and Characterization

  Qi-Lin LU;

  . 2013, 44(20): 2985-2989.

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  Cellulose nanocrystalline (CNC) was prepared from Pennisetum Sinese Roxb by hydrolysis with sulfuric acid. The effects of sulfuric acid concentration, reaction temperature and reaction time on the yield of CNC were optimized with response surface methodology. The mathematical model was established by using of the Design-Expert software. The results showed that quadratic model was the best model to describe the relationship between the yield of CNC and the factors. With the sulfuric acid concentration of 51%, reaction temperature of 60℃, and the reaction time of 120min, the yield of CNC arrived the highest value of 80% in our investigation extension. CNC is rod-like with the diameter of 20~30 nm, the length of 100~200 nm. The XRD spectra showed that the crystallinity of CNC is higher than Pennisetum Sinese Roxb fiber. The infrared spectra showed that CNC had similar structure to Pennisetum Sinese Roxb fiber.
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  TiO2 nanotube arrays fabricated by anodization

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  . 2013, 44(20): 2996-2998.

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  Abstract: TiO2 nanotube arrays were fabricated by anodization in the system of glycol electrolyte. The new composite structure of the bottom nanotube and upper nanowire with the length of 15um ~ 20um were prepared. The influences of the water contents in the electrolyte with respect to the composite structure was studied by two-step anodization. The results show that the composite structure can be obtained according to moderate etching rate of electrolyte and selective etching of the nanotube, when the glycol system electrolyte containing 0.4wt% NH4F and 2 vol% H2O.
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  Preparation of Fe-doped TiO2 by Polymer Network Method

  . 2013, 44(20): 2999-3002.

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  Fe/TiO2 powders were prepared by polymer network method using tetrabutyl titanate and ferric nitrate as raw materials, N-hydroxymethyl acrylamide amide as monomer, N, N′-methylene diacrylamide as network reagent. The effects of Fe doped concentration and the calcined temperature on performance of the TiO2 powders were studied. The heating effect, crystal structure and absorption spectrum of particles were characterized by TG-DTA, XRD and UV-Vis. The results showed that with the calcined temperature increased, TiO2 crystallite size increased. Fe doping greatly inhibited the increase of crystallite size and it can promote the phase transformation of TiO2 from anatase to rutile. The Fe doped concentration and calcined temperature had great influence on the optical absorption band edge. In the experimental conditions, when the Fe doped concentration was 1.5% and the optimal calcined temperature was 650℃, the optical absorption band edge of red shift was the most obvious.
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  Preparation and Properties of Lanthanum and Iron Co-doped TiO2/bentonite composite photocatalyst

  . 2013, 44(20): 3003-3006.

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  Lanthanum and iron co-doped TiO2/bentonite composite photocatalyst was prepared by ultrasonic-assisted sol-gel method. The micro-structure of materials were characterized by means of X-ray diffraction, IR spectroscopy and Uv-Vis absorption spectroscopy respectively．The activity of composite photocatalyst was evaluated by degradation of 2,4,6-trinitrotoluene(TNT)．The results showed that lanthanum and iron co-doped can restrain the growing of the grain size, and depress the change of the anatase phase．The absorption intensities of lanthanum and iron co-doped TiO2/bentonite increase. Appropriate quantity of lanthanum and iron can enhace the photocatalytic activities of TiO2/bentonite composite photocatalyst．The photocatalystic activity of the lanthanum and iron co-doped TiO2/bentonite composite photocatalyst doped with 0.5at% of lanthanum,0.05at% of iron and calcined under 400℃ was the best．
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  Preparation of magnetic MCM-41/CdS Composite and its visible-light photocatalytic performance

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  . 2013, 44(20): 3007-3011.

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  Magnetic MCM-41/CdS composite was prepared via a two-step precipitation method through depositing CdS on the magnetic MCM-41. XRD, HRTEM, UV-vis absorption spectra and VSM were used to characterize the magnetic MCM-41/CdS composite. Methylene Blue(MB) aqueous solution was used as a probe to evaluate the visible-light photocatalytic activity of magnetic MCM-41/CdS composite. The results showed that CdS was successfully deposited on the magnetic MCM-41, and magnetic MCM-41/CdS composite had higher visible-light photocatalytic activity than pure CdS. In addition, MCM-41/CdS composite could be easily separated in an external magnetic field.
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  Preparation of Ba(ZrTi)O3 nanotubes film by hydrothermal route

  . 2013, 44(20): 3012-3015.

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  Ba(ZrTi)O3 nanotubes were fabricated by hydrothermal method using Ti-Zr-O nanotube template which obtained via anodization of Ti25Zr substrate and Ba(OH)2 solution. The effect of Ba(OH)2.6H2O concentrations and hydrothermal temperatures on the microstructure of Ba(ZrTi)O3 nanotubes were investigated. The structural characteristics and surface morphology were examined by X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, and transmission electron microscopy, respectively. The results show that BaTi0.75Zr0.25O3 nanotubes with the diameter of 70±5 nm and the length of 6 μm were prepared successfully. The optimal process parameters for preparing BaTi0.75Zr0.25O3 nanotubes are shown as follows: the concentration of Ba(OH)2.6H2O is 0.08M and the hydrothermal temperature is 150℃.
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  Influence of initial pressure on SnO2 Nanoparticles Prepared by Gaseous Detonation

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  . 2013, 44(20): 3016-3019.

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  SnO2 nanoparticles prepared by detonation the mixed gas of hydrogen, oxygen and tin tetrachloride is a now method. Its polymorphs, morphology and particle size were characteried by means of XRD, TEM, HRTEM and Zetasizer Nano and summarized the influence of the initial pressure on the product. The results showed that the synthesized nano-tin dioxide is pure rutile phase, and a grain does not exist. With the improvement of the initial pressure ,the grain size of the tin dioxide is reduced, but the particcle size is larger, the particles are spherical and appear reunion, dispersion variation.
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  Preparation and Characterization of the Fe Series Polybasic Nano-Alloys by Room Temperature Solid-Solid Reaction

  ;Guo-Qing ZHONG

  . 2013, 44(20): 3020-3023.

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  The Fe series polybasic nano-alloys were prepared by room temperature solid-solid reaction with the transition metal chlorides and potassium borohydride as raw materials. The PVP was added as dispersant. The resultants were characterized by inductively coupled plasma emission spectroscopy, X-ray powder diffraction, transmission electron microscopy and thermal analysis. The results showed that the Fe-Ni-Co-B nano-alloy was mainly amorphous whisker with length of 100~200 nm and diameter of 2~4 nm, the average particle size of the Fe-Ni-Cu-B nano-alloy was about diameter of 20 nm. The catalytic properties of the iron series polybasic nano-alloys on the thermal decomposition of the ammonium perchlorate had been studied. The study showed that the two nano-alloys obviously reduced decomposition temperature of the pyrolysis process of ammonium perchlorate and enhanced decomposition heat.
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  Preparation, Characterization and Gas Sensitivity Studies of MWCNTs-doped Polyaniline nanocomposites

  Hiao Ying DU;wang jing

  . 2013, 44(20): 3024-3029.

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  0.02 wt% Multi-wall carbon nanotubes (MWCNTs) doped polyaniline (PANI) nanopowders were prepared by chemical polymerization of protonic acid method in 0℃ water bath. The pure PANI and 0.05 wt % MWCNTs doped PANI nanopowders were prepared by the same way. The morphology and structure of PANI, MWCNTs-doped PANI nanopowders were analyzed by XRD, FI-IR and FE-SEM. Gas sensors were fabricated based on PANI, 0.02 wt% MWCNTs-doped PANI and 0.05 wt% MWCNTs-doped PANI. The response sensitivity of gas sensors to NH3 was measured in NH3 concentration range of 10 ppm ~ 150 ppm. The response curves of three gas sensors were basically linearity. The response sensitivity of the gas sensor based on 0.02 wt% MWCNTs-doped PANI was the highest, the responses were 27.65 and 1.94 for 150 ppm NH3 and 10 ppm NH3, respectively. The stability of the gas sensor based on 0.02 wt% MWCNTs-doped PANI was tested, and the sensor showed good stability in three months. The sensing mechanism of MWCNTs-doped PANI gas sensor was analyzed.
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  Preparation and performance of alumina ultrafiltration membrane

  Shuang-Shuang Teng;Xiao Luo;;;;ma-tai DING;

  . 2013, 44(20): 3030-3034.

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  Alumina ultrafiltration membrane was prepared by sol-gel hydrothermal method. SEM and XRD were employed to characterize the crystal form, particle morphology, pore size distribution and thickness of membrane layer surface so as to achieve a good control of the membrane layer characteristic. In addition, flux, rejection, acid and alkaline resistances were also tested. The results showed that crystal form and particles surface morphology of ultrafiltration membrane could be efficiently controlled by treatment with hydrothermal method followed by sintering at suitable temperature. Pore size and pore size distribution can be well tuned by using different types PEG as dispersant agents. The thickness and cracking of membrane layer could be efficiently controlled by changing the concentration of the coating solution and by adding PVA. It was found that α- Al2O3 ultrafiltration membrane displayed a better acid and alkaline resistance than that of transition- state.
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  The synthesis of NiAl-LDH/montmorillonite composites by two methods

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  . 2013, 44(20): 3035-3039.

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  To obtain a new catalytic materials with good dispersion, carrier acid easy modulation and high thermal stability, the composites of NiAl-LDH/MMT was prepared respectively by intercalation method and in situ method. The compounds was characterized by XRD, IR, TG-DTA,BET and SEM measurement. The intercalation method is as follows：first, exfoliate the NiAl-LDH to get the LDH layers, then insert the exfoliated NiAl-LDH layers into the interlayers of MMT. The in situ method is that: first ,change the Na-MMT into NiAl-MMT, then add alkali into NiAl-MMT fluid to form a composite. The results shows that, both of the two methods had prepared composites with good crystallization. The LDH layers and MMT layers are layer by layer staggered alternately.The LDH layer’s hydroxyl removal temperature of the composites reachs to 525℃.
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  Preparation and characterization of polyaniline/attapulgite nanofiber

  Liang SHAO ;

  . 2013, 44(20): 3040-3044.

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  Core-shell conducting nanofibers SAM-ATP/PANI were prepared by the encapsulation of attapulgite (ATP) template with polyaniline (PANI) after the surface modification with anilino methyl triethoxysilane (AMTES) to form a self-assembled monolayer (SAM) on the surface of ATP needle-shaped particle (SAM-ATP). The nanofibers of 15.4 wt% SAM-ATP/PANI with a better uniformity and dispersity, and the conductivity of 15.4 wt% SAM-ATP/PANI nanofibers at room temperature was determined to be 2.3 × 10-4 S/cm, larger than pure PANI. Moreover, thermal stability of SAM-ATP/PANI nanofibers was clearly improved with the increasing of SAM-ATP. These trends were accompanied by significant structural changes as evidenced by Transmission electron microscopy, Fourier transform IR and UV–visible spectroscopy.
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  Hydrogen storage properties of nanostructured Mg-based hydrogen storage material with bituminous coal as binder

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  . 2013, 44(20): 3045-3048.

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  Nanostructured Mg-based hydrogen storage material with bituminous coal as binder and carbonized anthracite coal as milling aid was prepared by hydrogen reaction ball milling and heat treatment. The structure and hydrogen storage properties of the material were investigated, and the hydrogen absorption kinetics parameter was calculated. Results show that the carbon in the material can react with Mg, and Mg2C3 is generated when the material gets heat treated at 600 oC, while at 500 oC the nano-structured Mg particles are well binded with 15 wt.% of bituminous coal without the generation of Mg2C3. The hydrogen absorbing rate was enhanced with the increase of temperature, and the hydrogen uptake reached to 3.77 wt.% at 350 oC, 2 MPa H2 and a little reduction at 400 oC. According to Arrhenius equation, the apparent activation energy for the first order reaction of hydrogen absorbing within 300–350℃ is 56.6 kJ/mol H2. The initial and peak hydrogen desorption temperatures are 250 oC and 388 oC, respectively. In the hydriding process, the carbon in the material can combine a small amount of hydrogen which can be released in the form of alkane like methane and ethane.
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  Preparation and characterization of silica aerogel/mesophase pitch derived carbon foam

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  . 2013, 44(20): 3049-3052.

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  Silica sol was synthetized via sol-gel method by TEOS and ethanol, while mesophase derived carbon foam was prepared via spontaneous foaming method from coal tar pitch as precursor. Then silica aerogel/msophase derived carbon foam composite was obtained by immersion process at ambient pressure. The silica aerogel, mesophase derived carbon foam and silica aerogel/msophase derived carbon foam composite were characterized by XRD, SEM, thermal-detector and universal testing machine. The results indicated that the aerogel/msophase derived carbon foam composite showed good mechanical perfermance, and its thermal insulation property was better than single mesophase derived carbon foam. Potentially the silica aerogel/msophase derived carbon foam composite was expected to be applied as a novel thermal insulation material.