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Anomalous Enhancement of Mechanical Properties in the Ammonia Adsorbed Defective Graphene

View Article: PubMed Central - PubMed

ABSTRACT

Pure graphene is known as the strongest material ever discovered. However, the unavoidable defect formation in the fabrication process renders the strength of defective graphene much lower (~14%) than that of its perfect counterpart. By means of density functional theory computations, we systematically explored the effect of gas molecules (H2, N2, NH3, CO, CO2 and O2) adsorption on the mechanical strength of perfect/defective graphene. The NH3 molecule is found to play a dominant role in enhancing the strength of defective graphene by up to ~15.6%, while other gas molecules decrease the strength of graphene with varying degrees. The remarkable strength enhancement can be interpreted by the decomposition of NH3, which saturates the dangling bond and leads to charge redistribution at the defect site. The present work provides basic information for the mechanical failure of gas-adsorbed graphene and guidance for manufacturing graphene-based electromechanical devices.

No MeSH data available.


Related in: MedlinePlus

(a) The strain-stress curve for D-graphene. (b) The breaking strain for D-graphene adsorbed by H2, N2, NH3, CO, CO2 or O2 molecule.
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f3: (a) The strain-stress curve for D-graphene. (b) The breaking strain for D-graphene adsorbed by H2, N2, NH3, CO, CO2 or O2 molecule.

Mentions: Normally, a material’s ideal (intrinsic) strength can be traced down to its bond strength42. The bond strength, in principle, can be greatly affected by the amount of charge in the bond. Removing one atom from the nanosheet will have a significant impact on the charge distribution of the layer, resulting in weakening the bond strength. As a result, the ideal strength of the material would be reduced. For example, the P-graphene is able to sustain an ideal strain above 30% (Fig. 2a), while the unavoidable defects in fabrication process (e.g. carbon atom vacancies) can significantly affect its strength, i.e. decreasing to only 14.8% (Fig. 3a). The introduction of foreign atoms in the defect sites of graphene brings new electron to interact with the dangling bonds, which therefore affect the bond strength and thus change the strain of the host materials. Motivated by this rationale, we explore the gas adsorption on D-graphene in order to modulate the ideal strain for D-graphene as well as shed new lights on the underlying mechanism.


Anomalous Enhancement of Mechanical Properties in the Ammonia Adsorbed Defective Graphene
(a) The strain-stress curve for D-graphene. (b) The breaking strain for D-graphene adsorbed by H2, N2, NH3, CO, CO2 or O2 molecule.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5036057&req=5

f3: (a) The strain-stress curve for D-graphene. (b) The breaking strain for D-graphene adsorbed by H2, N2, NH3, CO, CO2 or O2 molecule.
Mentions: Normally, a material’s ideal (intrinsic) strength can be traced down to its bond strength42. The bond strength, in principle, can be greatly affected by the amount of charge in the bond. Removing one atom from the nanosheet will have a significant impact on the charge distribution of the layer, resulting in weakening the bond strength. As a result, the ideal strength of the material would be reduced. For example, the P-graphene is able to sustain an ideal strain above 30% (Fig. 2a), while the unavoidable defects in fabrication process (e.g. carbon atom vacancies) can significantly affect its strength, i.e. decreasing to only 14.8% (Fig. 3a). The introduction of foreign atoms in the defect sites of graphene brings new electron to interact with the dangling bonds, which therefore affect the bond strength and thus change the strain of the host materials. Motivated by this rationale, we explore the gas adsorption on D-graphene in order to modulate the ideal strain for D-graphene as well as shed new lights on the underlying mechanism.

View Article: PubMed Central - PubMed

ABSTRACT

Pure graphene is known as the strongest material ever discovered. However, the unavoidable defect formation in the fabrication process renders the strength of defective graphene much lower (~14%) than that of its perfect counterpart. By means of density functional theory computations, we systematically explored the effect of gas molecules (H2, N2, NH3, CO, CO2 and O2) adsorption on the mechanical strength of perfect/defective graphene. The NH3 molecule is found to play a dominant role in enhancing the strength of defective graphene by up to ~15.6%, while other gas molecules decrease the strength of graphene with varying degrees. The remarkable strength enhancement can be interpreted by the decomposition of NH3, which saturates the dangling bond and leads to charge redistribution at the defect site. The present work provides basic information for the mechanical failure of gas-adsorbed graphene and guidance for manufacturing graphene-based electromechanical devices.

No MeSH data available.


Related in: MedlinePlus