Atomistic simulation of tensile strength properties of graphene with complex vacancy and topological defects

Damasceno, Daniela Andrade; Rajapakse, R. K. N. D.; Mesquita, Euclides; Pavanello, Renato

doi:10.1007/s00707-020-02715-6

Cited by 12 publications

(4 citation statements)

References 42 publications

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“…The SW1 configuration was mechanically stronger compared to all other defects. Here, it is interesting to note that the same behaviour was observed for the zigzag graphene with the SW1 defect [50]. Compared to a pristine CGNR, the strength was reduced from 90.6 to 75.7 GPa and the failure strain from 0.23 to 0.15 for a SW1 defect, whereas for a 5-8-5 defect the strength reduced to 61.8 GPa and the strain to 0.12.…”

Section: Topological and Vacancy Defects In Cgnrsupporting

confidence: 69%

Atomistic Modelling of Size-Dependent Mechanical Properties and Fracture of Pristine and Defective Cove-Edged Graphene Nanoribbons

Damasceno

Mesquita

2020

Nanomaterials

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Cove-edged graphene nanoribbons (CGNR) are a class of nanoribbons with asymmetric edges composed of alternating hexagons and have remarkable electronic properties. Although CGNRs have attractive size-dependent electronic properties their mechanical properties have not been well understood. In practical applications, the mechanical properties such as tensile strength, ductility and fracture toughness play an important role, especially during device fabrication and operation. This work aims to fill a gap in the understanding of the mechanical behaviour of CGNRs by studying the edge and size effects on the mechanical response by using molecular dynamic simulations. Pristine graphene structures are rarely found in applications. Therefore, this study also examines the effects of topological defects on the mechanical behaviour of CGNR. Ductility and fracture patterns of CGNR with divacancy and topological defects are studied. The results reveal that the CGNR become stronger and slightly more ductile as the width increases in contrast to normal zigzag GNR. Furthermore, the mechanical response of defective CGNRs show complex dependency on the defect configuration and distribution, while the direction of the fracture propagation has a complex dependency on the defect configuration and position. The results also confirm the possibility of topological design of graphene to tailor properties through the manipulation of defect types, orientation, and density and defect networks.

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Section: Topological and Vacancy Defects In Cgnrsupporting

confidence: 69%

Atomistic Modelling of Size-Dependent Mechanical Properties and Fracture of Pristine and Defective Cove-Edged Graphene Nanoribbons

Damasceno

Mesquita

2020

Nanomaterials

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“…The exfoliation is effective to expose the topological defects and also the N dopants buried in carbon base. Meanwhile ε ∥ induces in‐plane broken in S‐1‐900, creating vacancies and topological defects at carbon edges, [ 25 ] as confirmed by ACTEM. The mechanism of catalytic sites formation is illustrated in Figure 2b.…”

Section: Resultsmentioning

confidence: 87%

“…This change is associated with a thermal exfoliation from molten halogen salt accompanied with intercalation of the carbon layers to expand the interlayer spacing, as shown in Figure 1c, the randomly selected interplanar spaces of the graphite phase (002) in average are 0.39, 0.38, or 0.35 nm, which are larger than that of 0.34 nm for graphite. [ 26 ] Meanwhile, the intercalation also creates abundant topological defects [ 25 ] in S‐1‐900, as confirmed by the aberration‐corrected transmission electron microscopy (ACTEM) images (Figure 1d and Figure S3, Supporting Information). The areas 1 and 2 with red dash squares in Figure 1d are enlarged as shown in Figure 1e and filtered image in Figure S4 (Supporting Information), which clearly reveals the formation of five‐sided regular pentagons (red lines) with hexagons around (yellow lines) at the armchair edges of graphene.…”

Section: Resultsmentioning

confidence: 91%

“…[22][23][24] The intercalation will weaken the Van der Waals force and expand the graphene layer spacing, thus exfoliating the graphene layers to expose abundant catalytic sites. Meanwhile, topological vacancy defects like pentagon would be also in-situ created [25] in G-N contained CNMs due to the stress effect from intercalation. Killing two birds with one stone, the intrinsic activity and the amount of active site in CNMs have both been improved via this strategy, resulting in a high activity for ORR in acidic medium.…”

Section: Introductionmentioning

confidence: 99%

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Constructing Graphitic‐Nitrogen‐Bonded Pentagons in Interlayer‐Expanded Graphene Matrix toward Carbon‐Based Electrocatalysts for Acidic Oxygen Reduction Reaction

Liu

Zheng

et al. 2021

Advanced Materials

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large-scale application of proton-exchange membrane fuel cells (PEMFCs). [1,2] However, most nonmetallic materials (e.g., organic compounds and ceramics) are not active for ORR in acid electrolytes due to their poor conductivity. Meanwhile, most metal-based materials are not acid-resistant, hindering their practical application in acid media. Despite great efforts devoted to the development of alternative materials, the activity of current non-Pt catalysts is still much inferior to Pt and its alloys. [3] Among the nonmetallic materials, carbon nanomaterials (CNMs), especially graphene, are an appropriate candidate with a host of merits, including high electrical conductivity, stable anticorrosion performance even under acidic condition, tunable physical and chemical properties. [3,4] However, the pristine graphene with symmetric local sp 2 -hybridized electronic structure is inert for electrocatalysis due to its electroneutrality. Surface functionalization (e.g., heteroatom doping such as N [5] ) is a good strategy to break the electroneutrality and induce asymmetry of charge distribution at neighbor carbon sites in graphene, [4,6] enhancing the electron donation to activate molecular oxygen. For example, the carbon π electrons in nitrogen-doped carbon materials are activated by conjugating with the lone-pair electrons from adjacent pyridinic-N (Py-N) [7][8][9] or graphitic-N (G-N), [10][11][12] which is proved to be active toward ORR. Besides, the nitrogen-doped carbon nanotube array also shows significantly improved activity than its intrinsic structure. [13] Other strategies including geometric structuring (increase specific surface area [14] and create porous structure [15] ) could also enhance the catalytic activity. The CNMs synthesized by these strategies are proved efficient in alkaline electrolytes, but far inferior to that of Pt/C catalyst in an acid medium. For example, Liang et al. reported the CNM named meso-PoPD [16] (total N content: 9.5 at%, Py-N content: 3.6%, with large mesopores) shows the half-wave potential of about 0.76 V in 0.1 m KOH, but only 0.42 V in 0.5 m H 2 SO 4 ; Parvez et al. reported a N-doped graphene [17] with the half-wave potential of 0.77 V in 0.1 m KOH, but only about 0.52 V of that in 0.5 m H 2 SO 4 . Therefore, it is a great challenge to further improve the ORR performance of CNMs in acidic electrolytes.The inferior activity for CNMS toward acidic ORR can be ascribed to two main reasons: 1) The intrinsic activity of Metal-free carbon-based materials with high electrocatalytic activity are promising catalysts for the oxygen reduction reaction (ORR) in several renewable energy systems. However, the performance of carbon-based materials is far inferior to that of Pt-based catalysts in acid electrolytes. Here, a novel carbonbased electrocatalyst is reported toward ORR in 0.1 m HClO 4 with half-wave potential of 0.81 V and better durability (100 h reaction time) than commercial 20 wt% Pt/C. It is achieved by constructing graphitic-nitrogen (GN)-bonded pentagons in graphitic carb...

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Research on the Defects in Graphene: Types and Effects on Mechanical and Thermal Properties

Wang

2021

Lecture Notes in Mechanical Engineering

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Atomistic simulation of tensile strength properties of graphene with complex vacancy and topological defects

Cited by 12 publications

References 42 publications

Atomistic Modelling of Size-Dependent Mechanical Properties and Fracture of Pristine and Defective Cove-Edged Graphene Nanoribbons

Atomistic Modelling of Size-Dependent Mechanical Properties and Fracture of Pristine and Defective Cove-Edged Graphene Nanoribbons

Constructing Graphitic‐Nitrogen‐Bonded Pentagons in Interlayer‐Expanded Graphene Matrix toward Carbon‐Based Electrocatalysts for Acidic Oxygen Reduction Reaction

Research on the Defects in Graphene: Types and Effects on Mechanical and Thermal Properties

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