Tri-layer graphene films produced by mechanochemical exfoliation of graphite

A Green Method for Graphite Exfoliation Using a Mechanochemical Route

“…A sudden change comes out with the discovery of molecular carbon allotropes as: fullerenes, carbon nanotubes and more recently, 2-D graphenes [1]. Graphenes are a single layer to less than ten stacked honeycomb carbon sheets [2] with sp 2 -bonding. The carbon atoms are arranged in a densely packed honeycomb lattice [3] joined with covalent bonds linked in the perpendicular stacking direction by weak Van der Wall's interaction.…”

“…Hence, the development of methods to prepare graphene without added functional groups is an important issue for industrial applications [5]. There exist a variety of methods for synthesizing graphenes: mechanical [3] and electrochemical exfoliation [4,6], micromechanical cleavage [2], microwave irradiation [11,12], reduction of graphite oxide [5], graphite expansion [13,14], liquid-phase exfoliation [15][16][17], etc. Some factors that determine the characteristics of graphene are: precursor morphology, particle size, and purity.…”

Preparation of low-dimensional carbon material-based metal nanocomposites using a polarizable organic/water interface

“…28 Furthermore, the employment of easily processable, liquid-phase exfoliated, reduced graphene oxide (rGO) materials to support deposition of noble metals at the organic/water interface has been widely investigated, mainly to prepare GR-based catalysts or electrode materials on solid substrates. 3,6,22,24,[29][30][31][32] The use of CVD GR offers a macroscopic material-visible to the naked eye-that has not been deliberately oxidized and consists of a high-quality, well-defined monolayer, as opposed to liquid-phase exfoliated rGO aggregates. 27 Functionalization of a free-standing CVD GR monolayer with noble metal (Au, Pt, Pd) nanoparticles, using a low-cost, two-step, solution chemistrybased process has been reported previously.…”

“…[19][20][21] The advantage of interfacial assembly of low-dimensional carbon species (GR and SWCNTs) is the ability to form macroscopic films spontaneously, from self-assembly of individual flakes and particles at liquid/liquid interfaces. [22][23][24][25] There is a small body of work on the localization of chemical vapor deposited (CVD) GR and multilayer graphene (MLG) materials (consisting of a small number, between 2 and about 10 of well-defined, countable, stacked GR layers) 26 at the polarizable organic/water interface. 27,28 This approach is exemplified using the electro-deposition of Pd nanoparticles (NPs) on free-standing CVD GR 27 or MLG and SWCNT layers.…”

Nanoestruturas de carbono (nanotubos, grafeno): Quo Vadis?

“…O método CVD, sob condições parecidas às utilizadas para o crescimento de nanotubos, mas utilizando-se substratos metálicos, possibilita o crescimento de monocamadas com baixo número de defeitos, mas também não corresponde, neste caso, a uma técnica de produção massiva (embora adequada para aplicações em microeletrônica, por exemplo). 20 Dentre as alternativas apresentadas até o momento, grandes quantidades de amostra podem ser preparadas pela exfoliação do grafite, 21,22 e neste caso o método mais abundante é totalmente dependente de rotas químicas, 23 como ilustrado esquematicamente na Figura 2. Esta rota consiste em três etapas distintas, iniciando pela oxidação química do grafite a óxido de grafite, na qual vários átomos de carbono sp 2 são oxidados a sp 3 , com a adição de grupamentos funcionais oxigenados; a seguir realiza-se a exfoliação do óxido de grafite em óxido de grafeno, pela separação das folhas bidimensionais contendo os grupamentos oxigenados; e finalmente o óxido de grafeno é quimicamente reduzido a grafeno, por meio de agentes redutores como hidrazina.…”