Co-carbonization of 9-chloroborafluorene and pitch; synthesis of B/C materials

Hu, Raymond; Chung, Tze-chiang

doi:10.1016/s0008-6223(97)00068-7

Cited by 13 publications

(6 citation statements)

References 9 publications

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“…More recently, BC 3 and B substituted C-nanotubes were also prepared, as well as the theoretical prediction of B effect to the H 2 binding energy . A few years ago, we reported a method to prepare boron-substituted carbon (B/C) materials, containing up to 7 mol% of boron atoms substitutionally incorporated in the C structure, by using boron-containing organic precursors and a pyrolysis process . The resulting B/C material at pyrolysis > 1500 °C becomes a stable, graphilic crystalline structure with an extremely low surface area (<3 m 2 /g).…”

mentioning

confidence: 99%

Synthesis of Microporous Boron-Substituted Carbon (B/C) Materials Using Polymeric Precursors for Hydrogen Physisorption

et al. 2008

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This paper discusses a new synthesis route to prepare microporous boron substituted carbon (B/C) materials that show a significantly higher hydrogen binding energy and physisorption capacity, compared with the corresponding carbonaceous (C) materials. The chemistry involves a pyrolysis of the designed boron-containing polymeric precursors, which are the polyaddition and polycondensation adducts between BCl3 and phenylene diacetylene and lithiated phenylene diacetylene, respectively. During pyrolysis, most of the boron moieties were transformed into a B-substituted C structure, and the in situ formed LiCl byproduct created a microporous structure. The microporous B/C material with B content > 7% and surface area > 700 m2/g has been prepared, which shows a reversible hydrogen physisorption capacity of 0.6 and 3.2 wt % at 293 and 77 K, respectively, under 40 bar of hydrogen pressure. The physisorption results were further warranted by absorption isotherms indicating a binding energy of hydrogen molecules of approximately 11 kJ/mol, significantly higher than the 4 kJ/mol reported on most graphitic surfaces.

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confidence: 99%

Synthesis of Microporous Boron-Substituted Carbon (B/C) Materials Using Polymeric Precursors for Hydrogen Physisorption

et al. 2008

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“…A viscous liquid (6.3 g) was obtained in 96% yield. The structure of the compound was confirmed by 1 H NMR, DEPT135- 13 C NMR and 11 B NMR in chloroform-d.…”

Section: Synthesis Of Dichloro(2-chloro-2-phenyl-vinyl)boranementioning

confidence: 90%

“…All 1 H and 13 C NMR spectra were recorded on a Bruker AM 300 instrument in 1,1,2,2-tetrachloroethane-d 2 at 110 o C. Bulk morphology in the polymer films was examined by Scanning Electron Microscopy (SEM), using a Topcon International Scientific Instruments ISI-SX-40 with secondary electron imaging. SEM samples were prepared from films cryo-fractured in liquid N 2 .…”

Section: Instrumentation and Materialsmentioning

confidence: 99%

“…With π-electron delocalization, the substitutional B atoms may serve as an internal p-type dopant and fundamentally change the C surface from an n-type (with rich π-electrons) to a p-type doped (oxidation) state that can have better interaction with σbonding electrons in a hydrogen molecule. In our earlier papers (11)(12)(13)(14), we have reported a novel approach to prepare B/C material. The chemistry is centered in a specifically designed boron-containing precursor, such as 9-chloroborafluorene (11), that contains an aromatic framework and oligomerization site.…”

Section: Introductionmentioning

confidence: 99%

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Physisorption of Hydrogen on Boron-Containing Carbon (B/C) Material Prepared by Organoborane Precursor

2007

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This paper discusses the synthesis of boron substituted carbon (B/C) materials by pyrolysis of two organic and polymeric precursors, which are prepared by chloroboration of phenylene acetylene and phenyl diacetylene, respectively. Some of the resulting B/C materials were evaluated in hydrogen physisorption from ambient to low temperatures under various hydrogen pressures. Evidently, through the precursor design it is possible to transform some B atoms in the precursor into B/C material by pyrolysis. Despite the dense structure (without significant porosity by SEM and BET), the B/C material with 1.6 wt% B content shows hydrogen absorption 0.7 and 2.15 wt% at 25 and -78 oC, respectively, under 1300 psi hydrogen pressure. The adsorption-desorption cycles were repeated many times without any detectable change. Apparently, the empty p-orbital in the substituted B atom increases the binding energy of hydrogen to the B/C surface of graphitic platelet , which is reversible by pressure and ambient temperature.

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“…Several papers have reported the production of carbon-doped materials via co-pyrolysis [5][6][7][8][9]. In this method, a heteroatom precursor is solubilised in the carbon precursor (coal-tar pitch, synthetic pitches, petroleum residues, etc.…”

Section: Introductionmentioning

confidence: 99%

Preparation of graphite/nano-SiC composites by co-pyrolysis of a petroleum residue with phenylsilanes

Carreira

Sanchez-Coronado

Narciso

et al. 2008

Journal of Analytical and Applied Pyrolysis

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Co-carbonization of 9-chloroborafluorene and pitch; synthesis of B/C materials

Cited by 13 publications

References 9 publications

Synthesis of Microporous Boron-Substituted Carbon (B/C) Materials Using Polymeric Precursors for Hydrogen Physisorption

Synthesis of Microporous Boron-Substituted Carbon (B/C) Materials Using Polymeric Precursors for Hydrogen Physisorption

Physisorption of Hydrogen on Boron-Containing Carbon (B/C) Material Prepared by Organoborane Precursor

Preparation of graphite/nano-SiC composites by co-pyrolysis of a petroleum residue with phenylsilanes

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