Wyniki wyszukiwania - BazTech

1

Effect of lead salts on phase, morphologies and photoluminescence of nanocrystalline PbMoO4 and PbWO4 synthesized by microwave radiation

Phuruangrat A., Kuntalue B., Artkla S., Promnopas S., Promnopas W., Thongtem S., Thongtem T.

Materials Science Poland

|

2016

|

Vol. 34, No. 3

529--533

EN

PbMoO4 and PbWO4 were successfully synthesized by microwave radiation using different lead salts (acetate, chloride, nitrate and sulfate) and Na2MO4 (M = Mo, W) in propylene glycol. The products were characterized by X-ray diffraction (XRD), scanning and transmission electron microscopy (SEM, TEM), Fourier transform infrared (FT-IR), Raman spectroscopy and photoluminescence (PL) spectroscopy. In this research, morphologies, crystallization and photoluminescence of the products were influenced by the kinetics of anions, including the detection of M–O (M = Mo, W) stretching modes in the (MO4)2 tetrahedrons. Photoluminescence of PbMoO4 synthesized from Pb(NO3)2 and of PbWO4 synthesized from PbCl2 showed the strongest blue emission due to the electronic diffusion in tetrahedrons at room temperature.

2

Microwave-assisted synthesis, characterization and photoluminescence of shuttle-like BaMoO4 microstructure

Phuruangrat A., Kuntalue B., Thongtem T., Thongtem S.

Materials Science Poland

|

2015

|

Vol. 33, No. 3

537--540

EN

Shuttle-like BaMoO4 microstructure has been successfully synthesized from Ba(NO3)2 4H2 O and Na2 MoO4 2H2 O as starting materials in ethylene glycol solvent containing 20 mL 5 M NaOH by microwave radiation at 180Wfor 30 min. The assynthesized BaMoO4 product was characterized by X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, Raman spectrophotometry, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and photoluminescence (PL) spectroscopy. XRD patterns revealed that the products was tetragonal BaMoO4 phase. SEM and TEM characterization showed that the product had a shuttle-like BaMoO4 microstructure. PL of the shuttle-like BaMoO4 microstructure showed a maximum emission at 466 nm excited by 280 nm wavelength.

3

Synthesis of nanocrystalline metal molybdates using cyclic microwave radiation

Phuruangrat A., Thongtem T., Thongtem S.

Materials Science Poland

|

2010

|

Vol. 28, No. 2

557--563

EN

Nanocrystalline compounds MMoO4 (M = Ca, Sr and Ba) were synthesized in propylene glycol using cyclic microwave radiation. XRD, TEM, SAED and EDX analyses revealed the presence of nanocrystallites of the phases containing the corresponding alkaline earth metals, Mo and O. The calculated lattice parameters and the crystallite sizes both increased with the increase in the atomic masses and the ionic radii of the divalent metals. Six different vibrations were detected using Raman spectroscopy, and very strong Mo-O stretching mode of [MoO4]2- tetrahedrons was observed using FTIR.

4

Characterization of nanocrystalline LiNi1-xCoxVO4 prepared by the polymerized complex method

Thongtem W. T., Phuruangrat A., Thongtem S.

Materials Science Poland

|

2009

|

Vol. 27, No. 1

43--49

EN

Nanocrystalline LiNi1-xCoxVO4 (x = 0.00, 0.25, 0.50, 0.75 and 1.00) was prepared from Li2CO3, Ni(NO3)2.6H2O, Co(NO3)2.6H2O and NH4VO3, using tartaric acid as a complexing agent, followed by 450 °C calcination for 12 h. TGA results show that nanocrystallites started to form at 450-550 °C. Inverse spinel LiNi1-xCoxVO4 was detected using the XRD and SAED methods. The calculated lattice parameter increased upon increasing Co concentration. It was in accordance with the increase in the particle size determined using TEM images. A stretching band of VO4 tetrahedra was detected at 651-820 cm-1 using FTIR. V-O vibrational bands analyzed with a Raman spectrometer were shifted to the lower wavenumbers, due to the increase of Co concentration. The selected elements were also analyzed using EDX and AAS to determine the stoichiometric values (x) of the oxides.