The channeling action of iron particles in the catalyzed hydrogenation of synthetic diamond

Chepurov, A. I.; Сонин, В. М.; Dereppe, Jean-Marie

doi:10.1016/s0925-9635(00)00256-9

Cited by 26 publications

(8 citation statements)

References 7 publications

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“…It has long been known that the reactions between carbon and gas are strongly catalyzed by metals such as iron, nickel and cobalt 34–36. The gasification reactions occur naturally in impure or doped carbon materials with metallic impurities, which in result of catalytic pitting and channeling 37–41. Recently, these solid‐catalyzed solid‐gas reactions have been explored as a method of carbon materials patterning 42–44.…”

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confidence: 99%

Vertically Aligned Graphene Layer Arrays from Chromonic Liquid Crystal Precursors

et al. 2010

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Progress in graphene synthesis has led to increased interest in the assembly of graphene into superstructures, and to the fabrication of novel ordered materials from graphene or engineered graphenic molecular building blocks. [1][2][3][4][5][6][7][8] Graphene monolayers typically deposit fl at on substrates or associate face-to-face to form horizontal stacked papers or multilayer coatings. [8][9][10][11] The opposite structure, vertically aligned graphene layer arrays on substrates ( Figure 1 A ), are more diffi cult to fabricate, but are expected to show a range of unique properties and behaviors. Their high concentration of edge-sites at the top surface would allow functionalization at high density for superhydrophobic/ philic coatings, high-redox-activity electrode surfaces, or chemically patterned surfaces for cell adhesion and guidance. The vertical layer orientation would allow rapid intercalation and deintercalation of lithium in high-discharge-rate thin fi lm batteries, [ 12 ] and would provide high Z -directional thermal/electrical conductivity. If also ordered in a second dimension, such arrays would be anisotropic in the substrate plane and provide unidirectional in-plane heat spreading or optical polarization. If the heights of arrays can be limited to below 50 nm, they may fi nd application as transparent conductive fi lms, [ 10 , 13 ] or as graphene nanoribbons where the ribbon width is set by the array height. Here we use chromonic liquid crystal precursors to fabricate vertically aligned graphene layer arrays (VAGLAs) on substrates and also demonstrate a method to achieve full two-dimensional order, which we defi ne as further control of graphene layer orientational patterns within the substrate plane using local shear-forces. We also demonstrate one example of a unique property of these arrays -the ability to etch Zdirectional nanopores by catalytic hydrogenation, in which cobalt nanoparticles tunnel vertically into and through the arrays as they track vertically receding edge-plane surfaces.A promising route to the desired vertical graphene array structure is one based on polyaromatic precursors, [ 2 ] which can adopt edge-on orientation on substrates. [ 5 , 14 , 15 ] Many polyaromatic compounds, however, do not retain supramolecular alignment upon carbonization, and also their solution or vapor deposition typically gives only short-range order in-plane. [ 2 ] Liquid crystal phases offer long-range order, but most discotic phases are high-temperature viscous liquids that are diffi cult to process and their supramolecular order can also be unstable during carbonization. [ 1 ] A promising solution to these challenges are so-called "chromonic liquid crystals" (CLCs), which combine graphenic disk assembly with water solubility. CLCs are formed from water soluble organic dyes which form massive π -stacks in aqueous solution that act as supramolecular rods. These structures then order into nematic liquid crystal phases through rod self-avoidance at high concentration [ 1 , 16-18 ]

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confidence: 99%

Vertically Aligned Graphene Layer Arrays from Chromonic Liquid Crystal Precursors

et al. 2010

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“…[46][47][48][49][50] Even with the catalysts that are ferromagnetic phases at room temperature we did not see any evidence that an external magnetic field could influence their behavior or set a preferred channeling direction. Successful magnetic steering was only observed for Co catalysts, which became the focus for a detailed study and the remainder of this article.…”

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confidence: 61%

“…Datta et al [49] have reported the use of iron to obtain nanotrenches in few-layer graphene through catalytic hydrogenation. It has been reported that channeling catalyst particles follow preferred crystallographic directions, [47][48][49][50] which, if fully understood, could lead to precise patterning through rule-based etching protocols. Such direct writing methods may offer advantages over static methods in terms of line resolution but this class of technique would be much more powerful and flexible, if one had a method to explicitly control the channeling directions or to change direction dynamically to produce complex and preselected channel patterns.…”

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confidence: 99%

A Magneto‐catalytic Writing Technique for Etching Complex Channel Patterns into Graphenic Carbons

Bulut¹,

Hurt²

2010

Advanced Materials

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“…In order to treat the crystals, we used hydrogenation by Fe particles. This technique has already demonstrated high etching rates on other diamond types [24,[40][41][42], while the distribution of metal particles on the diamond and the characteristics of the etched surface depend mainly upon the method of preparation of the etchant [47]. Our recent study on synthetic diamond crystals confirmed that the size of the pits can be decreased significantly [26].…”

Section: Discussionmentioning

confidence: 82%

“…Estimated concentrations of nitrogen in the form of A and B-centers are the following: In order to produce a porous surface, catalytic hydrogenation was carried out using a laboratory-made high-temperature water-cooled microfurnace according to the state assignment of the Institute of Geology and Mineralogy SB RAS. Fe particles were used as an etchant, and the procedure is described in our earlier publications [24,[40][41][42]. Hydrogenation is a chemical reaction between molecular hydrogen (H 2 ) and another compound (in particular graphite or diamond), usually in the presence of a catalyst such as Fe, Co, Ni, Pt, Pd.…”

Section: Methodsmentioning

confidence: 99%

Surface Porosity of Natural Diamond Crystals after the Catalytic Hydrogenation

et al. 2021

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The study of diamond surfaces is traditionally undertaken in geology and materials science. As a sample material, two natural diamond crystals of type Ia were selected, and their luminescence and nitrogen state was characterized. In order to etch the surface catalytic hydrogenation was performed using Fe particles as an etchant. Micromorphology of the surface was investigated by scanning electron and laser confocal microscopy. It was demonstrated that etching occurred perpendicular to the crystal surface, with no signs of tangential etching. The average depth of caverns did not exceed 20–25 μm with a maximal depth of 40 μm. It is concluded that catalytic hydrogenation of natural type Ia diamonds is effective to produce a porous surface that can be used in composites or as a substrate material. Additionally, the comparison of results with porous microsculptures observed on natural impact diamond crystals from the Popigai astrobleme revealed a strong resemblance.

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The channeling action of iron particles in the catalyzed hydrogenation of synthetic diamond

Cited by 26 publications

References 7 publications

Vertically Aligned Graphene Layer Arrays from Chromonic Liquid Crystal Precursors

Vertically Aligned Graphene Layer Arrays from Chromonic Liquid Crystal Precursors

A Magneto‐catalytic Writing Technique for Etching Complex Channel Patterns into Graphenic Carbons

Surface Porosity of Natural Diamond Crystals after the Catalytic Hydrogenation

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