Nanoporous carbon produced by ball milling

Abstract

A nanoporous structure was produced in the samples of graphite after ball milling at ambient temperature. The specific internal surface area of the micropores, as determined using the t-plot method, is higher than the external surface area of particles and mesopores. Phase transformations from hexagonal to turbostratic, and to amorphous structures were investigated using x-ray diffraction analysis and transmission electron microscopy. Formation of the nanoporous structure is associated with that of the disordered carbon. The disordered and nanoporous structure is probably fullerene-like in nature.

One-dimensional nanomaterials synthesized using high-energy ball milling and annealing process

“…The amorphous/disordered phases are the source of free C, B and N atoms as no vapor phase is present. The growth process is in a solid-state process, possibly driven by surface diffusion [19]. This mechanism is supported by other experimental observations.…”

“…Because the annealing temperature (1400 1C) is much lower than the melting point of graphite (43500 1C), carbon vapor should not be produced during the nanotube formation. The nanoporous and disordered structures created by HEBM [19] should have an important role in nanotube formation during annealing. Detailed growth mechanisms will be discussed later.…”

“…The new HEBM technique has produced many new metastable materials which cannot be synthesized using thermal equilibrium processes in past several decades [13,14], for example, amorphization of ZrNi alloys under a dynamic equilibrium between mechanical driven disordering or amorphization process and thermal reordering process [15], mechanical alloying of nanocrystalline compounds, nanoparticle-reinforced metal nanocomposite [16][17][18], and nanoporous materials [19]. Controlled reactive ball milling has produced nanosized particles of metal oxides [20], nitrides [21], hydrides [22] and carbides [23] at room temperature.…”

Synthesis of boron nitride nanotubes employing mechanothermal process and its characterization

“…Annealing of the ball-milled BN powder can be done either in NH 3 or N 2 atmosphere as the BN nanotube formation takes place by solid state nucleation and growth mechanism through a thermally activated process of surface diffusion [17]. It may be noted that in the present investigation the annealing of milled samples was carried out in the presence of N 2 gas.…”

Influence of bond defects on coiling of graphite

“…Graphite consists of stacks of parallel two-dimensional graphene sheets with carbon atoms being arranged in hexagonal rings through localized in-plane hybridised 2s, 2p x and 2p y (sp 2 ) orbitals. The individual sheets are weakly bonded by delocalized out-of-plane 2p z orbitals, which overlap at 901 to the graphene plane to give a delocalized p-electron system.…”