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Preparation and properties of magnetic iron oxide nanotubes

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Particuology 2008年第5期6卷 334-339页

作者： baoliang lv Yao Xu Dong Wu Yuhan Sun State Key Laboratory of Coal Conversion Institute of Coal Chemistry Chinese Academy of Sciences Taiyuan 030001 China Graduate University of the Chinese Academy of Sciences Beijing 100039 China

Magnetite （Fe3O4） nanotubes were prepared by reducing synthesized hematite （α-Fe2O3） nanotubes in 5%H2＋95% Ar atmosphere, and then maghemite （γ-Fe2O3） nanotubes were obtained by re-oxidizing the Fe3O4 nanotubes. The nanotube structure was kept from collapsing or sintering throughout the high temperature reducing and re-oxidizing processes. The coercivities of the Fe304 and γ-Fe2O3 nanotubes synthesized were found to be 340.22 Oe and 342.23 Oe, respectively, both higher than other nanostructures with the same phase and of similar size. Both adsorbed phosphate and the nanotube structure are considered responsible for this high coercivity.

关键词： Nanostructures Iron oxides Nanotubes Magnetic properties

Hydrothermal synthesis and characterization of NiS flower-like architectures

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Particuology 2012年第6期10卷 783-788页

作者： Hai Zhou baoliang lv Dong Wu Yuhan Sun Key Laboratory of Carbon Materials Institute of Coal ChemistryChinese Academy of Sciences Graduate University of the Chinese Academy of Science Low Carbon Conversion Center Shanghai Advanced Research InstituteChinese Academy of Sciences

Under the influence of thiocyanate anions （SCN-） and cetyltrimethyl ammonium bromide （CTAB）, NiS flower-like architectures were successfully synthesized by a one-step hydrothermal method. The syn-thesized flower-like architectures, with a multilayered and highly ordered texture, have diameters of several micrometers. X-ray powder diffraction （XRD） shows that the NiS flower-like architectures are rhombohedral crystalline. On the basis of condition-dependent experiments, the diffusion-limited aggregation （DLA） model and cage effect were used to explain the growth process of rhombohedral crystalline NiS flower-like architectures. Magnetic measurements showed that the coercivity （He） of the as-obtained NiS flower-like architectures was 102.14 Oe.

关键词： Nanostructures Chemical synthesis Electron microscopy Magnetic properties

Preparation of α-Fe_2O_3 Nanodisks by Blocking the Growth of (001) Plane

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Journal of Materials Science & Technology 2009年第2期25卷 155-158页

Based on the difference of hydroxy group configuration on the special adsorption and coordination of phosphate on the dispersed α-Fe2O3 nanodisks with diameter of 150-200 nm different planes of α-Fe2O3 nanoparticles, using （001） plane of α-Fe2O3, well-crystallized and well and thickness of 40-80 nm were synthesized via a hydrotherrnal method. The magnetic properties of synthesized nanodisks were investigated. It was found that the nanodisks possessed a saturation magnetization （Ms） of 0.38 emu/g, a rernanent magnetization （Mr） of 0.031 ernu/g and a coercivity of 452.91 Oe at room temperature. The Mr and coercivity of synthesized α-Fe2O3 nanodisks are higher and the Ms is lower than those of other previously reported α-Fe2O3 nanostructures.

关键词： Nanomaterials α-Fe2O3 Nanodisk Magnetic materials

Magnetic and electrochemical behavior of rhombohedral α-Fe_2O_3 nanoparticles with (104) dominant facets

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Particuology 2013年第3期11卷 327-333页

作者： Zhong Liu baoliang lv Dong Wu Yuhan Sun Yao Xu State Key Laboratory of Coal Conversion Institute of Coal ChemistryChinese Academy of Sciences Key Laboratory of Salt Lake Resources and Chemistry Qinghai Institute of Salt LakesChinese Academy of Sciences Low Carbon Conversion Center Shanghai Advanced Research InstituteChinese Academy of Sciences

Uniform rhombohedral α-Fe2O3 nanoparticles, -60nm in size, were synthesized via a triphenyl- phosphine-assisted hydrothermal method. Scanning electron micrograph （SEM） and transmission electron micrograph （TEM） analyses showed that the as-synthesized rhombohedral nanoparticles were enclosed by six （1 04） planes. The concentration of triphenylphosphine played an important role in morphological evolution of the α-Fe2O3 nanoparticles. The as-prepared rhombohedral nanoparticles possessed remanent magnetization Mr of 2.6 × 10^-3 emu/g and coercivity Hc of 2.05 Oe, both lower than those of other α-Fe2O3 particles with similar size, indicating their potential applications as superparamagnetic precursor materials. Furthermore, these rbombohedral α-Fe2O3 nanoparticles exhibited good sensor capability toward H2O2 with a linear response in the concentration range of 2-20 mM.

关键词： α-Fe2O3 Morphology Magnetic materials Chemical synthesis

Preparation,characterization and combustion properties of Zr/ZrH_2 particles coated with α-FeOOH crystal grains

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Particuology 2009年第3期7卷 169-174页

作者： baoliang lv Yao Xu Bo HOU Dong Wu Yuhan Sun State Key Laboratory of Coal Conversion Institute of Coal Chemistry Chinese Academy ofSdences Taiyuan 030001 China Graduate School of the Chinese Academy of Sciences Beijing 100049. China

Zr/ZrH2 particles with irregular morphologies and broad size distribution were uniformly coated with acicular α-FeOOH crystal grains via a facile route without using polymers or surfactants. The as-synthesized material was characterized by X-ray diffraction （XRD）, scanning electron microscopy （SEM）, energy dispersive X-ray （EDX）, UV-vis diffusion reflection （UV-vis） and Raman spectrometry. Based on these characterizations, the synthesis mechanism was explained in terms of combined heterogeneous nucleation and solid state transformation reaction. The presence of α-FeOOH coating greatly changed the combustion behavior of Zr/ZrH2 particles： the combustion lasting time decreased from 32 s for un-coated Zr/ZrH2 particles to 0.2 s for coated particles while the maximum temperature in the combustion process increased from 1510 ℃ to 2036℃.

关键词： Composite materials Coating Zr/ZrH2 α-FeOOH Solid state transformation Combustion

Facile synthesis of porous nitrogen-doped holey graphene as an efficient metal-free catalyst for the oxygen reduction reaction

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Nano Research 2017年第1期10卷 305-319页

作者： Li Qin Ruimin Ding Huixiang Wang Jianghong Wu Conghui Wang Chenghua Zhang Yao Xu Liancheng Wang baoliang lv State Key Laboratory of Coal Conversion Institute of Coal Chemistry Chinese Academy of Sciences Taiyuan 030001 China Key Laboratory of Carbon Materials Institute of Coal Chemistry Chinese Academy of Sciences Taiyuan 030001 China Synfuels China Technology Co. Ltd. Beijing 101407 China State Key Laboratory of Transient Optics and Photonics Xi'an Institute of Optics and Precision Mechanics Chinese Academy of Sciences Xi'an 710119 China University of Chinese Academy of Sciences Beijing 100049 China

Nitrogen-doped graphene is a promising candidate for the replacement of noble metal-based electrocatalysts for oxygen reduction reactions （ORRs）. The addition of pores and holes into nitrogen-doped graphene enhances the ORR activity by introducing abundant exposed edges, accelerating mass transfer, and impeding aggregation of the graphene sheets. Herein, we present a straightforward but effective strategy for generating porous holey nitrogen-doped graphene （PHNG） via the pyrolysis of urea and magnesium acetate tetrahydrate. Due to the combined effects of the in situ generated gases and MgO nanoparticles, the synthesized PHNGs featured not only numerous out-of-plane pores among the crumpled graphene sheets, but also interpenetrated nanoscale （5-15 nm） holes in the assembled graphene. Moreover, the nitrogen doping configurations of PHNG were optimized by post-thermal treatments at different temperatures. It was found that the overall content of pyridinic and quaternary nitrogen positively correlates with the ORR activity; in particular, pyridinic nitrogen generates the most desirable characteristics for the ORR. This work reveals new routes for the synthesis of PHNG-based materials and elucidates the contributions of various nitrogen species to ORRs.

关键词： porous holey N-dopedgraphene in situ templates post-thermal treatment oxygen reduction reaction

A simple vacuum sample chamber for small-angle X-ray scattering at Beijing synchrotron radiation facility

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Radiation Detection Technology and Methods 2019年第3期3卷 155-159页

作者： Zhenzhong Li Zhihong Li Fei Xie Dongfeng Li baoliang lv Institute of High Energy Physics Chinese Academy of SciencesBeijing 100049China College of Engineering Science University of Chinese Academy of SciencesBeijing 100049China Institute of Physical Science and Information Technology Anhui UniversityHefei 230601China Xingtai University Xingtai 054001HebeiChina State Key Laboratory of Coal Conversion Institute of Coal ChemistryChinese Academy of SciencesTaiyuan 030001China

Objective A vacuum sample chamber for SAXS measurement of solutions was developed to improve the signal-to-noise ratio of the instrument at Beijing Synchrotron Radiation Facility(BSRF).Methods We developed a vacuum sample chamber which could be connected to the upstream and the downstream vacuum tubes by *** and vertical linear slides were mounted in the vacuum chamber to adjust the sample position by 35 mm in the horizontal and vertical directions to align the sample in the light *** liquid sample holder of the chamber was sealed with polyimide film by squeezing instead of gluing to avoid the potential influence of sealant on the *** The chamber had been used for SAXS measurements of water and bovine serum albumin solution at *** results showed that the background scattering intensity in air was much higher than that in vacuum,especially in the smallangle area near the *** the q value is 0.142 nm−1,1.01 nm−1 and 1.25 nm−1,the background scattering intensity in air is 45,6.8 and 4.6 times of that in vacuum,*** the background-subtracted scattering curves of bovine serum albumin solution(10 mg/ml)in air and vacuum differ in intensity by a factor of about *** the q value is 2 nm−1,the signal-to-noise ratios of scattering intensity of BSA in air and vacuum are 0.79 and 8.51,*** We designed a simple vacuum sample chamber to be used on the SAXS instrument at 1W2A station of *** scattering of the background and protein solution in air and vacuum was tested and compared,and the signal-to-noise ratio was clearly improved.

关键词： Small-angle X-ray scattering Vacuum sample chamber Solution sample Signal-to-noise ratio