N. Wei

Beijing University of Chemical Technology, Peping, Beijing, China

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Publications (16)14.36 Total impact

  • P.-Y. Wu · L. Lan · S.-F. Ji · N. Wei · Z.-W. Lü · H. Liu
    [Show abstract] [Hide abstract] ABSTRACT: A series of Co-Ni 2P/SBA-15/cordierite monolithic catalysts were prepared by coating the slurry of the Co-Ni 2P/SBA-15 precursors on a pretreated cordierite support, and followed by temperature-programmed reduction in a H 2 flow. The samples were characterized by XRD, N 2 adsorption-desorption and XPS. The catalytic activities for the hydrodesulfurization (HDS) of dibenzothiophene (DBT) were evaluated. The results showed that Ni 2P phase was present in the all Co-Ni 2P/SBA-15/cordierite monolithic catalysts. The surface areas and pore volume of the Co-Ni 2P/SBA-15/cordierite monolithic catalysts slightly increased when Co was added to the Ni 2P/SBA-15/ cordierite monolithic catalyst. The Co-Ni 2P/SBA-15/cordierite monolithic catalyst with Co loading of 0.55wt% exhibited the highest conversion of 98.8% at 380 °C for DBT. The biphenyl (BP) selectivity was improved by adding the Co to the Ni 2P/SBA-15/cordierite monolithic catalysts.
    No preview · Article · Mar 2012 · Chinese Journal of Inorganic Chemistry
  • Zhenfeng Zhu · Yanli Zhang · Hui Liu · Na Wei
    [Show abstract] [Hide abstract] ABSTRACT: The original spherical α-Ni(OH)2 architectures with many cubic particles growing from the surface were successfully synthesized by a microwave-assisted hydrothermal method using urea as hydrolysis-controlling agent and polyethylene glycol (PEG) as surfactant. The NiO architectures with similar morphology were obtained by simple thermal decomposition of the precursor α-Ni(OH)2. The as-obtained products were well characterized by XRD, FTIR, TGA, SEM, TEM, UV–Vis and CVs. The experimental results showed that the diameter of spherical α-Ni(OH)2 architectures was in the range of 2–4 μm. The side length of the cubic particles was uniform about 200 nm. The cyclic voltammetric results showed that the reversible behavior of NiO electrode change better with the increasing of the cycle index. The original NiO we have prepared are expected to have good electrochemical behavior.
    No preview · Article · Feb 2012 · Superlattices and Microstructures
  • N. Wei · S. Ji · Y. Guan · H. Liu · C. Li
    [Show abstract] [Hide abstract] ABSTRACT: Ni 2P/SBA-15 precursors were prepared by co-impregnation method with nickel nitrate as nickel source, ammonium hydrogen phosphate as phosphorus and mesopore molecular sieve SBA-15 as support. Then the W was introduced into the precursors and the W-Ni 2P/SBA-15 precursors were converted into corresponding W-Ni 2P/SBA-15 catalysts after temperature-programmed reduction in flowing H 2. The structure of W-Ni 2P/SBA-15 was characterized by XRD, N 2 adsorption-desorption isotherms, NH 3-TPD, and XPS. The catalytic activity of W-Ni 2P/SBA-15 for the hydrodesulfurization of dibenzothiophene was evaluated. The result showed that only Ni 2P phase was formed in the W-Ni 2P/SBA-15. The specific surface area and the pore volume of W-Ni 2P/SBA-15 increased then decreased when W content increased. Both the stronger acid sites and the total acid amount of W-Ni 2P/SBA-15 obviously increased with the increase of W content, and so did the Ni δ+ and the P δ- content of the catalyst surface. W-Ni 2P/SBA-15 catalysts exhibited good catalytic performance of deep hydrodesulfurization of dibenzothiophene over 360°C, in which the direct desulfurization was the main desulfurization mechanism.
    No preview · Article · Dec 2011 · Shiyou Xuebao, Shiyou Jiagong/Acta Petrolei Sinica (Petroleum Processing Section)
  • Zhi Rong Suo · Hui Liu · Na Wei
    [Show abstract] [Hide abstract] ABSTRACT: The walnut-like α-Ni (OH)2 architectures have been successfully synthesized through a microwave-assisted hydrothermal method using urea as a hydrolysis-controlling agent and polyethylene glycol (PEG) as a surfactant. The NiO architectures with similar morphology were obtained by a simple thermal decomposition process of the precursor α-Ni (OH)2. The as-obtained products were well characterized by XRD, SEM, TEM, and FTIR. The experimental results shown that walnut-like α-Ni (OH)2 architectures with a diameter of 2-6 μm. The formation process of Ni (OH)2 architectures was observed by SEM via different hydrothermal reaction times.
    No preview · Article · Nov 2011
  • N. Wei · P.H. Zeng · S. Ji · P.F. Zhao · H. Liu · C.Y. Li
    [Show abstract] [Hide abstract] ABSTRACT: A series of La-Ni2P/SBA-15 catalysts with different La contents were prepared by impregnating nickel nitrate, diammonium hydrogen phosphate, and lanthanum nitrate on SBA-15 support and followed by TPR method. The structure of the catalysts was characterized by XRD, N2 adsorption-desorption and XPS. The catalytic performance of the catalysts for hydrodesulfurization (HDS) was evaluated using DBT as model compound. The results indicated that the addition of La increased the surface area and pore volume of the catalysts. On the surface of La-Ni2P/SBA-15 catalysts, La, Ni and P existed in the form of La3+, Niδ+ and Ni2+, Pδ- and P5+. The 4%La-Ni2P/SBA-15 catalyst had the highest DBT conversion, which could reach 98.4% at 360°C and exhibited excellent catalytic activity. The BP and CHB selectivity did not change when La was added to Ni2P/SBA-15 catalyst. The conversion of DBT mainly occurred through direct desulfurization and BP was main product.
    No preview · Article · Jun 2011
  • Zhenfeng Zhu · Na Wei · Hui Liu · Zuoli He
    [Show abstract] [Hide abstract] ABSTRACT: The Ni(OH)2 architectures with flower-like morphology assembled from nanosheets have been successfully synthesized through a microwave-assisted hydrothermal method using urea as a hydrolysis-controlling agent and polyethylene glycol (PEG) as a surfactant. The NiO architectures with similar morphology were obtained by a simple thermal decomposition process of the precursor Ni(OH)2. The as-obtained products were well characterized by XRD, TG-DTA, SEM, TEM, FTIR and UV–Vis. The experimental results shown that flower-like Ni(OH)2 architectures with a diameter of 2.5–4.0μm are assembled from nanosheets with a thickness of 10–20nm and width of 0.5–1.5μm. The UV–Vis experimental results shown that the absorption edge of the NiO architectures have a blue-shift with the increasing of the calcination temperature.
    No preview · Article · May 2011 · Advanced Powder Technology
  • [Show abstract] [Hide abstract] ABSTRACT: A facile method has been developed to synthesis hierarchical nickel oxide with spherical particle morphologies, high surface area of 234 m(2)/g and narrow pore distribution at 3.25 nm by controlled thermal decomposition of the nickel nitrate hydroxide precursors. The as-obtained products were well characterized by XRD, SEM, TEM (HRTEM), SAED, FTIR and N2 adsorption-desorption measurement. It was shown that the hierarchical NiO microsphere with the diameter about 2.0 mu m is composed of hexagonal nanoparticles with mesoporous structure. The prepared mesoporous materials were used as an adsorbent to remove the Congo red pollutant contained in the waste water, and they exhibited more favorable adsorptive properties than the mesoporous alumina powders with same surface area due to its special structural features.
    No preview · Article · May 2011
  • R. Zou · H. Liu · N. Wei · M. Li
    [Show abstract] [Hide abstract] ABSTRACT: The definition of the COMPASS Terrestrial Reference System, and the establishment and maintenance scheme of COMPASS TRF have been discussed in this paper, and simulated evaluations are carried out using IGS GPS stations and COMPASS stations. The effects of station distributions and the impact of intra-technique combination are investigated in details. The results of the simulation study reveals that about 22 globals distributed stations are needed for the COMPASS TRF establishment, and about 30 globals stations are required its long-term maintenance. It is also confirmed that the stability and reliability of the weekly TRF solution will be improved by the intra-technique combination.
    No preview · Article · Apr 2011
  • Z.-F. Zhu · N. Wei · H. Liu · Z.-L. He · D. Yang
    [Show abstract] [Hide abstract] ABSTRACT: The Ni(OH)2 architectures with flower-like morphology assembled from nanosheets have been successfully synthesized through a microwave-assisted hydrothermal method using urea as a hydrolysis-controlling agent and polyethylene glycol (PEG) as a surfactant. The NiO architectures with similar morphology were obtained by a simple thermal decomposition process of the precursor Ni(OH)2. The as-obtained products were well characterized by XRD, TG-DTA, SEM, TEM, FTIR and UV-Vis. The experimental results shown that flower-like Ni(OH)2 architectures with a diameter of 2.5-4.0μm are assembled from nanosheets with a thickness of 10-20nm and width of 0.5-1.5μm. The UV-Vis experimental results shown that the band gap of the as-synthesized NiO samples was about 3.27eV, which shows obvious red-shift compared with that of the bulk NiO. The electrochemical performance of the Ni(OH)2 was investigated by means of the experiment of cyclic voltammetry. The results indicated that it was reversible.
    No preview · Article · Mar 2011 · Gongneng Cailiao/Journal of Functional Materials
  • Source
    [Show abstract] [Hide abstract] ABSTRACT: Mesoporous titanium dioxide beads with high surface areas (over 90 m(2)/g) and tunable pore sizes (from 12.8 to 16.5 nm) were synthesized via a solvothermal process heating by microwave irradiation, with ammonia being used as both a source of nitrogen and a control agent for the mesoporous structure. Structural characterization indicated that the mesoporous TiO(2) beads were composed of nanocrystals and pores and the beads possess a optical band gap energy of 3.11 eV. The doping nitrogen was in the form of NH(x) or NO(x) species and was adsorbed on surface of the beads, which caused changes to the surface electronic structure. The results show that the samples which possess higher-order structure, large surface area and well-defined crystallinity have the best performance in photocatalytic activities exhibited as evaluated in the degradation of methylene blue.
    Full-text · Article · Mar 2011 · Journal of hazardous materials
  • P.-F. Zhao · S.-F. Ji · N. Wei · H. Liu · C.-Y. Li
    [Show abstract] [Hide abstract] ABSTRACT: A series of Al-Ni2P/SBA-15 catalysts with initial P/Ni molar ratio of 0.8 were prepared using (NH4)2HPO4 as a source of phosphorus, Ni(NO)3 as a source of nickel, and Al content from 1.06wt% to 6.35wt%. The catalysts were characterized by XRD, TEM and N2 adsorption-desorption. The catalytic performances of the hydrodesulfurization (HDS) were evaluated in a fixed-bed micro-reactor using dibenzothiophene (DBT) as the model compound. The results showed that the catalysts modified by Al still maintained the mesoporous structure. The Ni 2P phase was mainly observed in the Al-Ni2P/SBA-15 catalysts when Al content was less than 5.29wt%. The Ni2P phase and Ni12P5 phase were found when Al content was from 5.29wt% to 6.35wt%. The 3-Al-Ni2P/SBA-15 catalyst with Al content of 4.24wt% had the best catalytic activity for the HDS of the DBT. Under the reaction conditions of 3.0 MPa, 360 °C, the activity of the 3-Al-Ni 2P/SBA-15 catalyst can reach 99.0%.
    No preview · Article · Dec 2010 · Chinese Journal of Inorganic Chemistry
  • Z. F. Zhu · Z. L. He · J. Q. Li · D. G. Liu · N. Wei
    [Show abstract] [Hide abstract] ABSTRACT: A sonochemical–microwave hydrothermal method for preparing fluorinated mesoporous TiO2 microspheres was developed. Fabrication of mesoporous TiO2 and doping of fluorine were achieved by sonication and then hydrothermal treatment of a solution containing TiO2 precursor sol and sodium fluoride. The average diameter of as synthesised TiO2 microspheres was ∼500 nm. Since the sodium fluoride was doped, rod-like grains (12±0·5 nm) and microporous structure (∼10 nm) formed on the surface, he roughness was clearly increased, and the microspheres look like waxberries. UV-vis absorption spectra showed that samples within the wavelength range from 0 to 300 nm show strong UV absorption and 10 nm BM-shift, which was highly related to its microstructures. The TEM and high resolution TEM results showed a novel mechanism for fluorinated TiO2 microsphere formation, i.e. its rod-assembled mesoporous microstructures related to the absorption of water molecules on the surface of the microspheres.
    No preview · Article · Nov 2010 · Material Research Innovations
  • Z.-F. Zhu · Z.-L. He · J.-Q. Li · N. Wei · L.-Y. Guo
    [Show abstract] [Hide abstract] ABSTRACT: The self-assembled mesoporous microstructures of F-doped TiO2 microspheres were synthesized via gel-microwave-assisted hydrothermal method. The as-synthesized samples were characterized by SEM, TEM, XRD, XPS and PL. The growth mechanism of F-doped TiO2 microspheres and its mesoporous microstructures was also briefly analyzed. The results showed that the average diameter of microspheres were about 400 nm. Since sodium fluoride doped, nanocrystals((12 ± 0.5)nm) and mesoporous (about 10nm) formed and roughness clearly enhanced. The PL spectra show F does not result into a new PL phenomenon, but F dopant can enhance the PL intensity of TiO2 microspheres. The PL spectra showed that the as-prepared samples exhibited broad blue emission at 396 and 464nm, and its photoluminescence property was highly related to its microstructures.
    No preview · Article · Sep 2010 · Gongneng Cailiao/Journal of Functional Materials
  • Source
    [Show abstract] [Hide abstract] ABSTRACT: The TiO2 hollow microspheres were prepared by microwave-assisted solvothermal treatment without template. The morphology and the phase of TiO2 hollow microspheres were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), high resolution transmission electron microscopy (HR-TEM), and BET surface areas. The results show that the particles have hollow structures and the shell was covered by nanocrystals and have higher specific surface area. The possible formation mechanism of hollow TiO2 spherical structures has simply been proposed. The activity was evaluated by the photocatalytic degradation of methyl orange (MO). The results show that the particles having specific surface area show higher photocatalytic activity. It can be attribute to the doped F atoms and the creation of oxygen vacancies.
    Full-text · Article · Feb 2010 · Journal of Materials Science
  • N. Wei · C. Shi · M. Li · R. Zou
    [Show abstract] [Hide abstract] ABSTRACT: The evolution and state-of-the-art of IGS reference frame is reviewed, and the consistency of IGS reference frame and ITRF is analyzed. It also generally introduces IGS data processing strategy and its related effects on the consistency of IGS final products. Two experiments were designed to investigate the consistency of IGS final orbit and IGS05. and that of IGS final orbit, final clock and weekly SINEX.
    No preview · Article · Nov 2009 · Wuhan Daxue Xuebao (Xinxi Kexue Ban)/Geomatics and Information Science of Wuhan University
  • [Show abstract] [Hide abstract] ABSTRACT: The monolithic catalysts containing nickel phosphide precursors were prepared by dipping the silica sol containing nickel nitrate and phosphoric acid into the pretreated cordierite (Cord) support. Then, a series of Ni 2P/SiO2/Cord monolithic catalysts with different Ni contents were prepared by temperature-programmed reduction method in H 2 flow. The structure of the catalysts was characterized using X-ray diffraction (XRD), N2 adsorption-desorption and scanning electron microscope (SEM). The catalytic performances of the hydrodesulfurization (I IDS) were evaluated in a fixed-bed micro-reactor using dibenzothiophene (DBT) as the model compound. The XRD results indicated that the nickel phosphides were well dispersed on the surface of catalysts while the Ni content was less than 3.2wt.%. However, there was the Ni2P phase in the Ni 2P/SiO2/Cord catalysts while the NI content was more than 6.4wt%. The results of N2 adsorption-desorption isotherms showed that the pore size of the catalysts was around 3.6 nm. The SEM results show that the coating thickness of the cordierite support was about 20 μm. The active evaluation results indicated that the Ni2P/SiO2/Cord monolithic catalysts had very good catalytic performances for the HDS. The conversion of the DBT can reach 92.0% under the condition of the liquid hourly space velocity (LHSV) of 1.9 h-1 and reaction temperature at 360 °C in the Ni2P/SiO2/Cord monolithic catalysts with Ni content of 12.8wt%. Simultaneity, the selectivity of biphenyl (BP) and cyclohexylbenzene (CHB) were 69.8% and 30.2%, respectively. It was indicated that the mechanism of the HDS was mainly the direct desulfurization (DDS) over the 2P/SiO2/Cord catalysts.
    No preview · Article · Sep 2009 · Chinese Journal of Inorganic Chemistry