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کاربرد نوع شرط:
- جایگاه : پژوهشی
- مجله: Journal of Nanoanalysis
- نوع مقاله: Journal Article
- کلمات کلیدی: nanomaterial,Rietveld,Solid state method,As2Ni3O8
- چکیده:
- چکیده انگلیسی: Nanostructured As2Ni3O8 samples were synthesized via facile solid-state reactions at 850 and 950 °C for 8h using As2O3, Ni(CH3COO)2.2H2O and Ni(NO3)2.6H2O raw materials. The synthesized nanomaterials were characterized by powder X-ray diffraction (PXRD) technique and fourier-transform infrared (FTIR) spectroscopy. The rietveld analyses showed that the obtained materials were crystallized well in monoclinic crystal structure with the space group P121/c1. The lattice parameters of the targets were about a = 5.76 Å, b = 9.54 Å and c = 10.18 Å with β = 92.95 °. It was found that nickel nitrate created a highly crystalline and pure As2Ni3O8 structure. However, nickel acetate created the target with lower purity and crystal phase growth; it produced the samples with smaller crystallite sizes. Reaction temperature changing showed that the parameter affected on the crystal growth of the obtained materials. The morphologies of the synthesized materials were studied by field emission scanning electron microscopy (FESEM) technique. Ultraviolet-visible spectra showed that the synthesized As2Ni3O8 nanomaterials had strong light absorption in the ultraviolet-visible light region. The direct optical band gaps were 2.6 and 2.5 eV for S1 and S3, respectively. The data showed that the band gaps were decreased by increasing the reaction temperature. This is due to the increasing the crystallite sizes of the obtained materials.
- انتشار مقاله: 03-03-1397
- نویسندگان: Alireza Hakimyfard,Shahin Khademinia,Masumeh Rahimkhani
- مشاهده
- جایگاه : پژوهشی
- مجله: Journal of Nanoanalysis
- نوع مقاله: Journal Article
- کلمات کلیدی: crystal structure,Hydrothermal,Rietveld,Biginelli,Sr2Nb2O7
- چکیده:
- چکیده انگلیسی: Nano powders Eu3+ and Nd3+ - doped Sr2Nb2O7 were prepared by a low temperature hydrothermal
method at 120 ºC for 48 h followed by annealing at 400 ᵒC for 3 h among Sr(NO3)2
and Nb2O5, Eu2O3 and Nd2O3 raw materials at stoichiometric 1:1 Sr:Nb molar ratio. Characterization
of the synthesized materials was performed by X-ray powder diffraction (XRPD)
technique. FullProf program employing profile matching with constant scale factors was employed
for structural analysis. The results showed that the patterns had a main Sr2Nb2O7 orthorhombic
crystal structure with space group . FESEM images showed that the synthesized
nanomaterials had flower morphologies. Ultraviolet-visible spectra analysis showed that the
synthesized Eu3+ and Nd3+ - doped Sr2Nb2O7 nanomaterials had light absorption in the ultraviolet
light region. The direct optical band gap energies obtained from UV-Vis absorption spectra
were 3.45, 3.50 and 3.80 eV for pure Sr2Nb2O7, S2 and S4, respectively. The catalytic activity of
the obtained materials in the one-pot synthesis of the heterocyclic compounds 3,4-dihydropyrimidin-
2(1H)-ones (DHPMs) in Biginelli reaction is investigated. The optimized 0.03 g of the
catalyst, 95 ºC reaction temperature, and 60 min reaction time are used for the other Biginelli
reactions in this work.- انتشار مقاله: 31-04-1396
- نویسندگان: Shahin Khademinia,Mahdi Behzad
- مشاهده
- جایگاه : پژوهشی
- مجله: International Journal of Nano Dimension
- نوع مقاله: Journal Article
- کلمات کلیدی: Dye degradation,Malachite Green,Nano-photocatalyst,Bandgap,Magnesium aluminate spinel
- چکیده:
- چکیده انگلیسی: Spinel MgAl2O4 nanopowders were synthesized by one-step solid state reactions using Al(NO3)3.9H2O and MgSO4 raw materials at stoichiometric 1 : 2, Mg : Al molar ratio at a constant reaction temperature of 1000 ºC for 8 h (S1), 10 h (S2) and 24 h (S3). The synthesized materials were characterized by powder X-ray diffraction (PXRD) technique. Structural analyses were performed by FullProf program making use of profile matching with constant scale factors. The results showed that the patterns had a cubic MgAl2O4 structure similar to the space group . Through textural analysis BJH (Barrette Joiner Halenda) and BET (Brunauer Emmett Teller) methods, the obtained materials were evaluated in terms of average pore size, specific surface area and average pore volume .The morphology of the obtained materials was studied by FESEM images. Ultraviolet–visible (UV-Vis) spectra showed that the nanostructured MgAl2O4 powders possessed strong light absorption properties in the ultraviolet-visible region. Direct optical band gap energies were calculated as 3.4, 2.9 and 3.1 eV for S1, S2 and S3, respectively. The photocatalytic performance of the synthesized nanomaterials was investigated for the degradation of pollutant Malachite Green (MG) in aqueous solutions under solar light. Optimum conditions (0.2 mL H2O2, 25 mg catalyst and 40 min catalytic reaction time for the removal of 80 mL of 100 ppm MG solution) were modeled and achieved by the design expert software for S1. The degradation yield in the condition was 100 % for S1.
- انتشار مقاله: 20-02-1397
- نویسندگان: Sakineh Parvarinezhad,Mahdi Salehi,Shahin Khademinia
- مشاهده
- جایگاه : پژوهشی
- مجله: International Journal of Nano Dimension
- نوع مقاله: Journal Article
- کلمات کلیدی: Hydrothermal,Optical property,Cadmium Sulfide,Crystal Phase,Purity
- چکیده:
- چکیده انگلیسی: Sub-micrometer-sized CdS spheres were synthesized by hydrothermal and solvothermal reactions using Cd(NO3)2.4H2O and CH4N2S raw materials at a constant stoichiometric 1 : 2, Cd : S molar ratio. Various conditions such as solvent type (water and/or ethanol), reaction time and temperature were examined for the synthesis of the targets. The synthesized materials were characterized by powder X-ray diffraction (PXRD) technique and fourier-transform infrared (FTIR) spectroscopy. Crystal structure study was performed in a comparison mode to investigate the crystalline phase purity and growth of the obtained CdS materials when the reaction conditions were changed. The PXRD data indicated that the as-synthesized materials were crystallized well in a hexagonal crystal system with the space group P63mc. However, the crystal phase growth study showed that a cubic crystal system of CdS was obtained as a second crystal phase in the mixture. The morphologies of the synthesized materials were studied by field emission scanning electron microscopy (FESEM) technique. The data showed that the reaction solvent had a critical influence on the morphology of the obtained materials. Ultraviolet-visible spectra showed that the synthesized CdS materials had strong light absorption in the ultraviolet-visible light regions. The calculated direct optical band gap energies of the obtained materials were in the ranges of 1.90-2.30 eV.
- انتشار مقاله: 20-12-1396
- نویسندگان: Leila Kafi-Ahmadi,Robabe Mohammadzadeh-Hesar,Shahin Khademinia
- مشاهده