TY  - JOUR
AU  - Jokić, Bojan M.
AU  - Mitrić, Miodrag
AU  - Radmilović, Velimir
AU  - Drmanic, Sasa
AU  - Petrović, Rada
AU  - Janaćković, Đorđe T.
PY  - 2011
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/4187
AB  - High temperature hydrothermal syntheses, using calcium nitrate tetrahydrate, sodium dihydrogen phosphate and urea as precursors, and characterization of hydroxyapatite (HAp) whiskers are reported herein. The morphology and chemical composition of the crystals from a monetite to a hydroxyapatite phase were controlled by varying the starting concentrations of the precursors and the solution pH through the amount of urea that is decomposed during heating. X-ray diffraction (XRD) analysis, infrared spectroscopy (IR), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM) and high-resolution TEM (HRTEM) were used to investigate the products of the syntheses in order to find the optimum reaction conditions for obtaining the desired morphology and phase composition. Different morphologies ranging from single crystals of monetite through rods and plates of hydroxyapatite with different size distribution to whisker-like single hydroxyapatite crystal were achieved by simply varying the starting concentration of urea. Structural refinement of the hydroxyapatite whiskers confirmed a strong preferential orientation along the c-axis direction of the hexagonal crystal structure, which was significantly different from the usually observed random crystal orientation. TEM and SEM analysis of the apatite whiskers confirmed single crystal structure with the a c-axis orientation parallel to the long axis of the whiskers, with sizes up to 150 mu m in length, 10 mu m in width and with a thickness of about 300 nm, that grew from the same centre of nucleation, forming flaky-like particles. (C) 2010 Elsevier Ltd and Techna Group Sri. All rights reserved.
T2  - Ceramics International
T1  - Synthesis and characterization of monetite and hydroxyapatite whiskers obtained by a hydrothermal method
VL  - 37
IS  - 1
SP  - 167
EP  - 173
DO  - 10.1016/j.ceramint.2010.08.032
ER  - 

@article{
author = "Jokić, Bojan M. and Mitrić, Miodrag and Radmilović, Velimir and Drmanic, Sasa and Petrović, Rada and Janaćković, Đorđe T.",
year = "2011",
abstract = "High temperature hydrothermal syntheses, using calcium nitrate tetrahydrate, sodium dihydrogen phosphate and urea as precursors, and characterization of hydroxyapatite (HAp) whiskers are reported herein. The morphology and chemical composition of the crystals from a monetite to a hydroxyapatite phase were controlled by varying the starting concentrations of the precursors and the solution pH through the amount of urea that is decomposed during heating. X-ray diffraction (XRD) analysis, infrared spectroscopy (IR), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM) and high-resolution TEM (HRTEM) were used to investigate the products of the syntheses in order to find the optimum reaction conditions for obtaining the desired morphology and phase composition. Different morphologies ranging from single crystals of monetite through rods and plates of hydroxyapatite with different size distribution to whisker-like single hydroxyapatite crystal were achieved by simply varying the starting concentration of urea. Structural refinement of the hydroxyapatite whiskers confirmed a strong preferential orientation along the c-axis direction of the hexagonal crystal structure, which was significantly different from the usually observed random crystal orientation. TEM and SEM analysis of the apatite whiskers confirmed single crystal structure with the a c-axis orientation parallel to the long axis of the whiskers, with sizes up to 150 mu m in length, 10 mu m in width and with a thickness of about 300 nm, that grew from the same centre of nucleation, forming flaky-like particles. (C) 2010 Elsevier Ltd and Techna Group Sri. All rights reserved.",
journal = "Ceramics International",
title = "Synthesis and characterization of monetite and hydroxyapatite whiskers obtained by a hydrothermal method",
volume = "37",
number = "1",
pages = "167-173",
doi = "10.1016/j.ceramint.2010.08.032"
}

Jokić, B. M., Mitrić, M., Radmilović, V., Drmanic, S., Petrović, R.,& Janaćković, Đ. T.. (2011). Synthesis and characterization of monetite and hydroxyapatite whiskers obtained by a hydrothermal method. in Ceramics International, 37(1), 167-173.
https://doi.org/10.1016/j.ceramint.2010.08.032

Jokić BM, Mitrić M, Radmilović V, Drmanic S, Petrović R, Janaćković ĐT. Synthesis and characterization of monetite and hydroxyapatite whiskers obtained by a hydrothermal method. in Ceramics International. 2011;37(1):167-173.
doi:10.1016/j.ceramint.2010.08.032 .

Jokić, Bojan M., Mitrić, Miodrag, Radmilović, Velimir, Drmanic, Sasa, Petrović, Rada, Janaćković, Đorđe T., "Synthesis and characterization of monetite and hydroxyapatite whiskers obtained by a hydrothermal method" in Ceramics International, 37, no. 1 (2011):167-173,
https://doi.org/10.1016/j.ceramint.2010.08.032 . .

TY  - JOUR
AU  - Elezovic, Nevenka R.
AU  - Babić, Biljana M.
AU  - Radmilović, Velimir
AU  - Gajic-Krstajic, Ljiljana M.
AU  - Krstajic, Nedeljko V.
AU  - Vracar, Ljiljana M.
PY  - 2011
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/4475
AB  - The kinetics of the hydrogen oxidation reaction (HOR) was studied at Pt nanoparticles supported on niobia-doped titania (Pt/N-T). The catalyst support, with the composition of 0.05NbO(2.5-delta)-0.995TiO(2) (0 LT delta LT 1), was synthesized by a modified sol gel procedure and characterized by the BET and X-ray diffraction (XRD) techniques. The specific surface area of the support was found to be 70 m(2) g(-1). The XRD analysis revealed the presence of the anatase TiO(2) phase in the support powder. No peaks indicating the existence of Nb-compounds were detected. Pt/N-T nanocatalyst was synthesized by the borohydride reduction method. Transmission electron microscopy revealed a quite homogenous distribution of the Pt nanoparticles over the support, with a mean particle size of about 3 nm. The electrochemical active surface area of Pt of 42 +/- 14 m(2) g(-1) was determined by the cyclic voltammetry technique. The kinetics of the HOR was investigated by linear sweep voltammetry at a rotating disc electrode in 0.5 mol dm(-3) HClO(4) solution. The determined value of the Tafel slope of 35 mV dec(-1) and an exchange current density of 0.45 mA cm(-2) per real surface area of the Pt are in good accordance with those already reported in the literature for the HOR at polycrystalline Pt and Pt nanocatalysts in acid solutions. This new catalyst exhibited better activity for the HOR in comparison with Pt nanocatalyst supported on Vulcan (R) XC-72R high area carbon.
T2  - Journal of the Serbian Chemical Society
T1  - A novel platinum-based nanocatalyst at a niobia-doped titania support for the hydrogen oxidation reaction
VL  - 76
IS  - 8
SP  - 1139
EP  - 1152
DO  - 10.2298/JSC100823100E
ER  - 

@article{
author = "Elezovic, Nevenka R. and Babić, Biljana M. and Radmilović, Velimir and Gajic-Krstajic, Ljiljana M. and Krstajic, Nedeljko V. and Vracar, Ljiljana M.",
year = "2011",
abstract = "The kinetics of the hydrogen oxidation reaction (HOR) was studied at Pt nanoparticles supported on niobia-doped titania (Pt/N-T). The catalyst support, with the composition of 0.05NbO(2.5-delta)-0.995TiO(2) (0 LT delta LT 1), was synthesized by a modified sol gel procedure and characterized by the BET and X-ray diffraction (XRD) techniques. The specific surface area of the support was found to be 70 m(2) g(-1). The XRD analysis revealed the presence of the anatase TiO(2) phase in the support powder. No peaks indicating the existence of Nb-compounds were detected. Pt/N-T nanocatalyst was synthesized by the borohydride reduction method. Transmission electron microscopy revealed a quite homogenous distribution of the Pt nanoparticles over the support, with a mean particle size of about 3 nm. The electrochemical active surface area of Pt of 42 +/- 14 m(2) g(-1) was determined by the cyclic voltammetry technique. The kinetics of the HOR was investigated by linear sweep voltammetry at a rotating disc electrode in 0.5 mol dm(-3) HClO(4) solution. The determined value of the Tafel slope of 35 mV dec(-1) and an exchange current density of 0.45 mA cm(-2) per real surface area of the Pt are in good accordance with those already reported in the literature for the HOR at polycrystalline Pt and Pt nanocatalysts in acid solutions. This new catalyst exhibited better activity for the HOR in comparison with Pt nanocatalyst supported on Vulcan (R) XC-72R high area carbon.",
journal = "Journal of the Serbian Chemical Society",
title = "A novel platinum-based nanocatalyst at a niobia-doped titania support for the hydrogen oxidation reaction",
volume = "76",
number = "8",
pages = "1139-1152",
doi = "10.2298/JSC100823100E"
}

Elezovic, N. R., Babić, B. M., Radmilović, V., Gajic-Krstajic, L. M., Krstajic, N. V.,& Vracar, L. M.. (2011). A novel platinum-based nanocatalyst at a niobia-doped titania support for the hydrogen oxidation reaction. in Journal of the Serbian Chemical Society, 76(8), 1139-1152.
https://doi.org/10.2298/JSC100823100E

Elezovic NR, Babić BM, Radmilović V, Gajic-Krstajic LM, Krstajic NV, Vracar LM. A novel platinum-based nanocatalyst at a niobia-doped titania support for the hydrogen oxidation reaction. in Journal of the Serbian Chemical Society. 2011;76(8):1139-1152.
doi:10.2298/JSC100823100E .

Elezovic, Nevenka R., Babić, Biljana M., Radmilović, Velimir, Gajic-Krstajic, Ljiljana M., Krstajic, Nedeljko V., Vracar, Ljiljana M., "A novel platinum-based nanocatalyst at a niobia-doped titania support for the hydrogen oxidation reaction" in Journal of the Serbian Chemical Society, 76, no. 8 (2011):1139-1152,
https://doi.org/10.2298/JSC100823100E . .

TY  - JOUR
AU  - Babić, Biljana M.
AU  - Kaluđerović, Branka V.
AU  - Vracar, Ljiljana M.
AU  - Radmilović, Velimir
AU  - Krstajic, Nedeljko V.
PY  - 2007
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/3286
AB  - A carbon cryogel, synthesized by carbonization of a resorcinol/formaldehyde cryogel and oxidized in nitric acid, was used as catalyst Support for Pt nanoparticles. The Pt/C catalyst was prepared by a modified polyol synthesis method in an ethylene glycol (EG) solution. Characterization by nitrogen adsorption showed that the carbon cryogel support and the Pt/C catalyst were mesoporous materials with high specific surface areas (S-BET GT 400 m(2) g(-1)) and large mesoporous Volumes. X-Ray diffraction of the catalyst demonstrated the successful reduction of the Pt precursor to metallic form. TEM Images of the Pt/C catalyst and Pt particle size distribution showed that the mean Pt particle size was about 3.3 nm. Cyclic voltammetry (CV) experiments at various scan rates (from 2 to 200 mV s(-1)) were pet-formed in 0.5 mol dm(-3) HCIO4 solution. The large capacitance of the oxidized carbon cryogel electrode, which arises from a combination of the double-layer capacitance and pseudocapacitance, associated with the participation of surface redox-type reactions was demonstrated. For the oxidized carbon cryogel, the total specific capacitance determined by I1/C vs. v(0.5) extrapolation method was found to be 386 F g-l. The hydrogen oxidation reaction at the investigated Pt/C catalyst proceeded as an electrochemically reversible, two-electron direct discharge reaction.
T2  - Journal of the Serbian Chemical Society
T1  - Characterization of a surface modified carbon cryogel and a carbon supported Pt catalyst
VL  - 72
IS  - 8-9
SP  - 773
EP  - 785
DO  - 10.2298/JSC0709773B
ER  - 

@article{
author = "Babić, Biljana M. and Kaluđerović, Branka V. and Vracar, Ljiljana M. and Radmilović, Velimir and Krstajic, Nedeljko V.",
year = "2007",
abstract = "A carbon cryogel, synthesized by carbonization of a resorcinol/formaldehyde cryogel and oxidized in nitric acid, was used as catalyst Support for Pt nanoparticles. The Pt/C catalyst was prepared by a modified polyol synthesis method in an ethylene glycol (EG) solution. Characterization by nitrogen adsorption showed that the carbon cryogel support and the Pt/C catalyst were mesoporous materials with high specific surface areas (S-BET GT 400 m(2) g(-1)) and large mesoporous Volumes. X-Ray diffraction of the catalyst demonstrated the successful reduction of the Pt precursor to metallic form. TEM Images of the Pt/C catalyst and Pt particle size distribution showed that the mean Pt particle size was about 3.3 nm. Cyclic voltammetry (CV) experiments at various scan rates (from 2 to 200 mV s(-1)) were pet-formed in 0.5 mol dm(-3) HCIO4 solution. The large capacitance of the oxidized carbon cryogel electrode, which arises from a combination of the double-layer capacitance and pseudocapacitance, associated with the participation of surface redox-type reactions was demonstrated. For the oxidized carbon cryogel, the total specific capacitance determined by I1/C vs. v(0.5) extrapolation method was found to be 386 F g-l. The hydrogen oxidation reaction at the investigated Pt/C catalyst proceeded as an electrochemically reversible, two-electron direct discharge reaction.",
journal = "Journal of the Serbian Chemical Society",
title = "Characterization of a surface modified carbon cryogel and a carbon supported Pt catalyst",
volume = "72",
number = "8-9",
pages = "773-785",
doi = "10.2298/JSC0709773B"
}

Babić, B. M., Kaluđerović, B. V., Vracar, L. M., Radmilović, V.,& Krstajic, N. V.. (2007). Characterization of a surface modified carbon cryogel and a carbon supported Pt catalyst. in Journal of the Serbian Chemical Society, 72(8-9), 773-785.
https://doi.org/10.2298/JSC0709773B

Babić BM, Kaluđerović BV, Vracar LM, Radmilović V, Krstajic NV. Characterization of a surface modified carbon cryogel and a carbon supported Pt catalyst. in Journal of the Serbian Chemical Society. 2007;72(8-9):773-785.
doi:10.2298/JSC0709773B .

Babić, Biljana M., Kaluđerović, Branka V., Vracar, Ljiljana M., Radmilović, Velimir, Krstajic, Nedeljko V., "Characterization of a surface modified carbon cryogel and a carbon supported Pt catalyst" in Journal of the Serbian Chemical Society, 72, no. 8-9 (2007):773-785,
https://doi.org/10.2298/JSC0709773B . .