Oxidative pit formation in pristine, hydrogenated and dehydrogenated graphene

Jones, Jason D.; Morris, C.F.; Verbeck, Guido F.; Pérez, Jose

doi:10.1016/j.apsusc.2012.10.161

Cited by 9 publications

(15 citation statements)

References 41 publications

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“…The hole outlined with a red dotted line in We now turn to a discussion of our results above. The anisotropically etched edges in our work are consistently armchair-oriented, in contrast to the zigzag-oriented edges or isotropic holes reported previously for oxidative graphene etching [19][20][21][22][23][24][25] and remote hydrogen plasma etching. 30,31 Vacuum annealing graphene at high temperatures in situ in the TEM has previously been reported to result in primarily armchair edges.…”

Section: Resultssupporting

confidence: 54%

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Oxidation of Suspended Graphene: Etch Dynamics and Stability Beyond 1000 °C

et al. 2019

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We study the oxidation of clean suspended mono-and few-layer graphene in real-time by in situ environmental transmission electron microscopy. At an oxygen pressure below 0.1 mbar we observe anisotropic oxidation in which armchair-oriented hexagonal holes are formed with a sharp edge roughness below 1 nm. At a higher pressure, we observe an increasingly isotropic oxidation, eventually leading to irregular holes at a pressure of 6 mbar. In addition, we find that few-layer flakes are stable against oxidation at temperatures up to at least 1000 °C in the absence of impurities and electron beam-induced defects. These findings show first that the oxidation

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Section: Resultssupporting

confidence: 54%

“…17 To date however, different groups have variously reported the process to result in holes with armchair, 18 zigzag [19][20][21][22] or isotropically etched edges. [23][24][25] The substrate in particular has been shown to affect the morphology of the etched structures. In one study (Ref.…”

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confidence: 99%

Oxidation of Suspended Graphene: Etch Dynamics and Stability Beyond 1000 °C

et al. 2019

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“…Based on the DFT calculation results, a two‐step mechanism for oxidation of graphene has been proposed: When exposed to O 2 , (1) the bare vacancies in graphene are quickly saturated by ether and carbonyl groups and (2) the ether and carbonyl groups at the defect sites further activate the dissociation of O 2 leading to the formation of larger lactone groups, which could directly desorb CO or CO 2. This two‐step oxidation process leads to the etching of graphene with the formation of pits, as observed in recent experiments …”

Section: Group IV Elemental Monolayers: Graphene Silicene and Germasupporting

confidence: 62%

“… Li et al . have shown oxidation induced strong hole doping in graphene at temperature from 200 to 300°C as revealed by Raman spectra, and the formation of etching pits at 500°C in O 2 /Ar gas flow for 2 h as seen in Figure …”

Section: Group IV Elemental Monolayers: Graphene Silicene and Germamentioning

confidence: 95%

Physics and chemistry of oxidation of two‐dimensional nanomaterials by molecular oxygen

Wang

Pandey

Karna

2016

WIREs Comput Mol Sci

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The discovery of graphene has inspired extensive interest in two-dimensional (2D) materials, and has led to synthesis/growth of additional 2D materials, generally referred to as 'Beyond Graphene'. Notable among the recently discovered exotic 2D materials are group IV elemental monolayers silicene and germanene, group V elemental monolayer phosphorene, and binary monolayers, such as hexagonal boron nitride (h-BN), and molybdenum disulfide (MoS 2 ). Environmental effect on the physical and chemical properties of these 2D materials is a fundamental issue for their practical applications in devices operating under ambient conditions, especially, exposure to air often leads to oxidation of nanomaterials with significant impact on the functional properties and performances of devices built with them. In view of its importance, we present here a review of the recent experimental and theoretical studies on the oxidation of 2D materials focusing on the relationship between the oxidation process and the energy values which can be calculated by first principles methods. The complement of experiments and theory facilitates the understanding of the underlying oxidation process in terms of cohesive energy, energy barrier to oxidation and dissociation energy of oxygen molecule for 2D materials including graphene, silicene, germanene, phosphorene, h-BN, and MoS 2 .

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“…(4) The above formulated interpretation (model) is direct opposite to the supposition (model) of a number of researchers, those believe in occurrence of hydrogen desorption (dehydrogenation) processes, mainly, from the external epitaxial graphene surfaces.And it is direct opposite to the supposition -model of many scientists that the diffusion of hydrogen along the graphenesubstrate interface is negligible. (5) In this connection, it is expedient to take into account also some other related experimental results, for instance (Stolyarova et al, 2009;Riedel et al, 2009;Riedel et al, 2010;Goleret al, 2013;Jones et al, 2012;Lee et al, 2012), on the peculiarities of the hydrogenationdehydrogenation processes in epitaxial graphenes, particularly, in the graphene-substrare interfaces.…”

Section: On the Thermodynamic Characteristics And Atomic Mechanisms Omentioning

confidence: 99%

On the hydrogenation-dehydrogenation of graphene-layer-nanostructures: Relevance to the hydrogen on-board storage problem

Nechaev¹,

Veziroğlu²

2015

Int. J. Phys. Sci.

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Herein, results of thermodynamic analysis of some theoretical and experimental [thermal desorption (TDS), scanning tunneling microscopy (STM), scanning tunneling spectroscopy (STS), high-resolution electron energy loss spectroscopy/low-energy electron diffraction (HREELS/LEED), photoelectron spectroscopy (PES), angle-resolved photoemission spectroscopy (ARPES), Raman spectroscopy and others] data on "reversible" hydrogenation and dehydrogenation of some graphene-layernanostructures are presented. In the framework of the formal kinetics and the approximation of the first order rate reaction, some thermodynamic quantities for the reaction of hydrogen sorption (the reaction rate constant, the reaction activation energy, the per-exponential factor of the reaction rate constant) have been determined. Some models and characteristics of hydrogen chemisorption on graphite (on the basal and edge planes) have been used for interpretation of the obtained quantities, with the aim of revealing the atomic mechanisms of hydrogenation and dehydrogenation of different graphene-layersystems. The cases of both non-diffusion rate limiting kinetics and diffusion rate limiting kinetics are considered. Some open questions and perspectives remain in solving the actual problem in effective hydrogen on-board storage; using the graphite nanofibers (GNFs) is also considered.

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Oxidative pit formation in pristine, hydrogenated and dehydrogenated graphene

Cited by 9 publications

References 41 publications

Oxidation of Suspended Graphene: Etch Dynamics and Stability Beyond 1000 °C

Oxidation of Suspended Graphene: Etch Dynamics and Stability Beyond 1000 °C

Physics and chemistry of oxidation of two‐dimensional nanomaterials by molecular oxygen

On the hydrogenation-dehydrogenation of graphene-layer-nanostructures: Relevance to the hydrogen on-board storage problem

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