A carbon composite based on pyrolyzed diphthalocyanines for immobilization of high-level waste from nuclear industry

Tikhonov, V. I.; Kapustin, V. K.; Лебедев, В. Т.; Sovestnov, A. E.; Bairamukov, V. Yu.; Mishin, K. Ya.

doi:10.1134/s1066362216050167

Cited by 6 publications

(18 citation statements)

References 7 publications

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“…The unavoidable high‐temperature heat‐treatment will destroy the structure of precursors and result in complicated chemical and electronic structure of the elements in M/N/C catalysts ,. The relative amount of N species would change according to the heat‐treatment temperature.…”

Section: Introductionmentioning

confidence: 99%

Comparative Study of the Oxygen Reduction Reaction on Pyrolyzed FePc in Acidic and Alkaline Media

et al. 2018

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Transition‐metal and nitrogen co‐doped carbon materials (M/N/C) have received increasing attention as electrocatalysts for the oxygen reduction reaction (ORR). M/N/C catalysts usually exhibit distinct ORR catalytic activity between acidic and alkaline media. The origin of such pH‐dependent activity is so far unclear. Herein, we investigate the dependence of ORR activity of FePc/C catalysts on the pyrolysis temperature (300–1000 °C) in both acidic and alkaline media to speculate the difference between active sites in the different media. The highest ORR activity is achieved at 800 °C and 500 °C in acidic and alkaline media, respectively. In particular, at 600–800 °C, the ORR activity increases greatly with increasing pyrolysis temperature in acidic medium, whereas it decreases in alkaline medium, indicating different active sites present in the two media. Thermal decomposition analysis of FePc suggests that highly active sites in acidic medium are formed through the decomposition of FePc or Fe‐N4 structures at 600–800 °C after releasing phthalonitrile (C6H5−C2N2), whereas intact FePc or Fe‐N4 incorporated in the carbon matrix are the main active sites in alkaline medium. XPS measurements show that there is a good relationship between the ORR activity and metal N in alkaline medium. This study is of significance to the development of highly active non‐precious metal catalysts.

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Section: Introductionmentioning

confidence: 99%

Comparative Study of the Oxygen Reduction Reaction on Pyrolyzed FePc in Acidic and Alkaline Media

et al. 2018

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“…Doped diamonds were synthesized using special precursors being the carbon matrices with encapsulated Eu atoms. These materials, pyrolyzates with composition EuCX (X ~ 30-40), we prepared from diphthalocyanines (EuPc2) [9,11] in which molecules the planar C32H16N8 ligands (Pc) are firmly linked through a metal atom (M = Eu) (Figure 1). First, for the synthesis of the LnPc2, the organic component, o-phthalonitrile, was placed into a quartz reactor and washed with argon flow [9].…”

Section: Methodsmentioning

confidence: 99%

“…These materials, pyrolyzates with composition EuCX (X ~ 30-40), we prepared from diphthalocyanines (EuPc2) [9,11] in which molecules the planar C32H16N8 ligands (Pc) are firmly linked through a metal atom (M = Eu) (Figure 1). First, for the synthesis of the LnPc2, the organic component, o-phthalonitrile, was placed into a quartz reactor and washed with argon flow [9]. At a constant passage of argon (~0.5 l/min), the temperature in the reactor was raised to 220-250°C.…”

Section: Methodsmentioning

confidence: 99%

“…During pyrolysis in Ar atmosphere (900°C), such molecules, composed of two planar ligands connected by metal atom, lost mainly light elements (H, N). As a result, in a molecule the ligands with free bonds could be linked and a metal atom became closed in the carbon shell (~1 nm in size) [9]. We supposed also an encapsulation of few metal atoms in a common shell by combining several molecules into small globules forming porous matrix where the metal atoms are firmly kept and released only by heating above 1200°C when amorphous carbon transformed into graphite [9,10].…”

Section: Introductionmentioning

confidence: 99%

“…As a result, in a molecule the ligands with free bonds could be linked and a metal atom became closed in the carbon shell (~1 nm in size) [9]. We supposed also an encapsulation of few metal atoms in a common shell by combining several molecules into small globules forming porous matrix where the metal atoms are firmly kept and released only by heating above 1200°C when amorphous carbon transformed into graphite [9,10]. To convert Eu-containing pyrolyzates into diamonds, we have applied the HPHT method using also catalytic additive (pentaerythritol).…”

Section: Introductionmentioning

confidence: 99%

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X-ray Exited Optical Luminescence of Eu in Diamond Crystals Synthesized at High-pressure High-temperature

Лебедев¹,

Shakhov²,

Vul³

et al. 2022

Preprint

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Diamond powders with inclusions of europium atoms were synthesized at high pressure (7.7 GPa) and temperature (1800oC) from a mixture of pentaerythritol, C(CH2OH)4, and pyrolyzate of diphthalocyanine (C64H32N16Eu) served as a special precursor. In prepared diamonds by X-ray fluorescence spectroscopy, we have found the concentration of Eu atoms of 51±5 ppm that is by two orders of magnitude greater than that in known natural and synthetic diamonds. X-ray diffraction, SEM, X-ray exited optical luminescence, Raman and IR spectroscopy have confirmed the formation of diamond monocrystals of high quality with em-bedded Eu atoms and a nitrogen content of ~500 ppm. Numerical simulation has allowed us de-termine the energy cost of 5.8 eV needed for the incorporation of a single Eu atom with adjacent vacancy into growing diamond crystal (528 carbons).

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Atomic-Force-Microscopy Analysis of Uranium Bis-Phthalocyanine and Its Pyrolysed Derivatives

Bairamukov

Лебедев

Tikhonov

2018

J. Synch. Investig.

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A carbon composite based on pyrolyzed diphthalocyanines for immobilization of high-level waste from nuclear industry

Cited by 6 publications

References 7 publications

Comparative Study of the Oxygen Reduction Reaction on Pyrolyzed FePc in Acidic and Alkaline Media

Comparative Study of the Oxygen Reduction Reaction on Pyrolyzed FePc in Acidic and Alkaline Media

X-ray Exited Optical Luminescence of Eu in Diamond Crystals Synthesized at High-pressure High-temperature

Atomic-Force-Microscopy Analysis of Uranium Bis-Phthalocyanine and Its Pyrolysed Derivatives

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