Investigation of carbon microspheres prepared by solid-phase pyrolysis of metal-free phthalocyanine

Manukyan, Aram; Mirzakhanyan, A. A.; Khachatryan, T. K.; Badalyan, G. R.; Arzumanyan, Grigory; Sharoyan, É. G.

doi:10.3103/s1068337213010076

Cited by 8 publications

(17 citation statements)

References 15 publications

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“…Obviously, all this is due to the increased disorder in the PP MFPc and decreased degree of nanocrystallites graphitization. Note, that a similar dependence was observed in the spectra of X-ray diffraction of these samples, where the Bragg peak from graphite planes (002) in the PP MFPc is much broader [9].…”

Section: Resultssupporting

confidence: 75%

“…Microspheres samples were synthesized by solid-phase pyrolysis method of organic compounds, as described in our works [9][10][11]. Earlier, the same method was applied to prepare Ni/C, Cu/C nanocomposites and Ni 1-x Cu x nanoalloys in different carbon matrices [10][11][12][13].…”

Section: Experimental Techniquementioning

confidence: 99%

“…In our previous research [9], carbon microspheres with a diameter of ~3 µm having a strong signal of electron paramagnetic resonance (EPR) were obtained by solid-phase pyrolysis of metal-free phthalocyanine (MFPc) H 2 C 32 N 8 H 16 . Since the samples, apart from carbon, contain a certain amount of nitrogen (5-10 at%), so one of the reasons of paramagnetism could be the uncompensated spins resulting from the substitution of carbon atoms by nitrogen.…”

Section: Introductionmentioning

confidence: 99%

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Structure and magnetic properties of carbon microspheres prepared by solid-phase pyrolysis of organic compounds

Manukyan¹,

Mirzakhanyan²,

Khachaturyan³

et al. 2015

J. Contemp. Phys.

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Abstract⎯Carbon microspheres with a mean diameter of 3-3.5 µm were prepared by solid-phase pyrolysis of polyethylene and metal-free phthalocyanine. Morphology, structure and magnetic properties of the samples were investigated by electron microscopy, Raman spectroscopy, magnetometry and electron paramagnetic resonance. Carbon microspheres are composed of graphitic nanocrystallites with longitudinal sizes of 10-15 nm. The samples reveal strong paramagnetism, which in the case of metal-free phthalocyanine pyrolysis is 3 times higher (~5×10 19 spin/g) due to the unpaired spins of impurity nitrogen atoms.

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Section: Resultssupporting

confidence: 75%

Section: Experimental Techniquementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Structure and magnetic properties of carbon microspheres prepared by solid-phase pyrolysis of organic compounds

Manukyan¹,

Mirzakhanyan²,

Khachaturyan³

et al. 2015

J. Contemp. Phys.

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“…As seen, the nearly spherical nanoparticles are sufficiently homogeneously dispersed in carbon matrix. Note that there is also a certain amount of carbon microspheres of 2-3 μm diameter in the matrix (more about them see in [11,12]). …”

Section: Resultsmentioning

confidence: 97%

“…As seen, there is a considerable difference between samples synthesized at different temperatures. Comparison with tabulated data [13] shows that a broad peak at ≈25° corresponds to partially graphitized carbon microspheres (d 002 ≈ 0.345 nm) [11,12], while four more narrow peaks in the spectrum (Fig. 3a) relate to Zn nanocrystallites with hexagonal symmetry.…”

Section: Resultsmentioning

confidence: 98%

Characterization of zinc and zinc cyanide nanoparticles in carbon matrices prepared by solid-phase pyrolysis of zinc-phthalocyanine

et al. 2016

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Abstract⎯Using solid-phase pyrolysis of Zn-phthalocyanine (ZnC 32 H 16 N 8 ), we have prepared zinc and zinc cyanide nanoparticles in carbon matrices with a zinc concentration of 3 at %. The structure and composition of samples were investigated by the methods of scanning electron microscopy, X-ray diffraction, and Raman spectroscopy. It is shown that at low pyrolysis temperature (700°C) only the Zn nanoparticles are formed, whereas at higher temperature (900°C) a certain amount of Zn(CN) 2 nanoparticles are also synthesized. The mean diameter of nanoparticles is about 150 nm, and their size distribution has a logarithmically normal shape.

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Structural, Morphological and Magnetic Properties of Nickel-Carbon Nanocomposites Prepared by Solid-Phase Pyrolysis of Ni Phthalocyanine

Manukyan

Gyulasaryan

Ginoyan

et al. 2016

NATO Science for Peace and Security Series B: Physics and Biophysics

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Nickel-carbon nanocomposites have been synthesized by the solid-phase pyrolysis of nickel-phthalocyanine at temperatures in the range 600-1100 ı C and synthesis duration time up to 300 min. Nickel nanoparticles of various size have been obtained, which are embedded in carbon nanotubes (CNT), nanofibers and encapsulated in the graphite-like shell. A formation of metallic nanoparticles with diameters in the range 5-40 nm takes place at pyrolysis temperatures lower than 700 ı C. The temperature of 700 ı C is a threshold for the beginning of the CNTs growth. At these temperatures, the CNTs have diameters 20 nm and the aspect ratio 100. A rise of the pyrolysis temperature leads to the increase of the CNTs average diameters. An analysis of the formation mechanisms of the metal-carbon nanocomposites has made it possible to determine that the CNT growth is caused by catalytic properties of nickel. In the process of interaction of Ni with amorphous carbon at high temperatures, nanoparticles form around themselves the graphitelike shells. Investigations of magnetic characteristics have shown that the main mass of Ni ferromagnetic nanoparticles has a single-domain and a vortex (pseudosingle domain) nature. We have detected the presence of superparamagnetic Ni nanoparticles and carbon paramagnetic centers in the nickel-carbon nanocomposite.

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Investigation of carbon microspheres prepared by solid-phase pyrolysis of metal-free phthalocyanine

Cited by 8 publications

References 15 publications

Structure and magnetic properties of carbon microspheres prepared by solid-phase pyrolysis of organic compounds

Structure and magnetic properties of carbon microspheres prepared by solid-phase pyrolysis of organic compounds

Characterization of zinc and zinc cyanide nanoparticles in carbon matrices prepared by solid-phase pyrolysis of zinc-phthalocyanine

Structural, Morphological and Magnetic Properties of Nickel-Carbon Nanocomposites Prepared by Solid-Phase Pyrolysis of Ni Phthalocyanine

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