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Fracture Toughnesses and Crack Growth Angles of Single-Layer graphyne Sheets

Acta Mechanica Solida Sinica 2019年第3期32卷 339-355页

作者： Zonghuiyi Jiang Rong Lin Junhua Zhao Jiangsu Key Laboratory of Advanced Food Manufacturing Equipment and Technology Jiangnan University Wuxi 214122 China Institute of Mechanics and Advanced Materials School of Mechanical Engineering Jiangnan University Wuxi 214122 China

Recently, Shang et al.(Angew Chem Int Ed 57(3):774-778,2018) have developed a method to synthesize ultrathin (around 1.9 nm) graphyne nanosheets. We reported here the mixed-mode I-II fracture toughnesses and crack growth angles of single-layer graphyne sheets using molecular dynamics (MD) simulations and the finite element (FE) method based on the boundary layer model, respectively. The various carbon-carbon bonds of graphyne sheets in the FE method are equated with the nonlinear Timoshenko beams based on the Tersoff-Brenner potential, where all the parameters of the nonlinear beams are completely determined based on the continuum modeling. All the results from the present FE method are reasonable in comparison with those from our MD simulations using the REBO potential. The present results show that both the critical stress intensity factors (SIFs) and the crack growth angle strongly depend on the chirality and loading angle q @= 90° and #= 0° representing pure mode I and pure mode II, respectively). Meanwhile, the fracture properties of single-layer cyclicgraphene and supergraphene sheets are also studied in order to compare with those of the graphyne sheets. The critical equivalent SIFs are derived as 1.55 graphyne)graphyne)< 2.49 nN A-3^2 and 1.42 < Keq-su (super)< 2.95 nN A_3//2 using the FE method. These findings should be of great help for understanding the fracture properties of carbon allotropes and designing the carbon-based nanodevices.

关键词： Fracture toughness graphyne Molecular dynamics Finite element

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Rational design of graphyne-based dual-atom site catalysts for CO oxidation

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Nano Research 2023年第1期16卷 343-351页

作者： Zhenwei Zhang Liang Zhang Xiaoyang Wang Yuan Feng Xiangwen Liu Wenming Sun Department of Chemistry Beijing Key Laboratory for Optical Materials and Photonic DevicesCapital Normal UniversityBeijing 100048China Linyi Vocational University of Science and Technology(Linyi Institute of Industrial Technology) Linyi 276000China Dassault Systemes(Shanghai)Information Technology Co. Ltd.Shanghai 200120China Institute of Analysis and Testing Beijing Academy of Science and Technology(Beijing Center for Physical and Chemical Analysis)Beijing 100094China TianHe Supercomputing Center of Huaihai Linyi 276000China

There are increasing concerns about the environmental impact of rising atmospheric carbon monoxide concentrations,thus it is necessary to develop new catalysts for efficient CO *** on first-principles calculations,the potential ofγ-graphyne(GY)as substrate for metals in the 4th and 5th periods under single-atom and dual-atoms concentration modes has been systematically *** was found that single-atom Co,Ir,Rh,and Ru could effectively oxidate CO molecules,especially for single ***,proper atoms concentration could boost the CO oxidation activity by supplying more reaction centers,such as Rh^(2)/*** was determined that two Rh atoms in Rh^(2)/GY act different roles in the catalytic reaction:one structural and another *** tests suggest that substituting the structural Rh atom in the center of acetylenic ring by Co or Cu atom is a possible way to maintain the reaction performance while reducing the noble metal *** systemic investigation will help in understanding the fundamental reaction mechanisms on GY-based *** emphasize that properly exposed frontier orbital of functional metal atom is crucial in adsorption configuration as well as entire catalytic *** study constructs a workflow and provides valuable information for rational design of CO oxidation catalysts.

关键词： density functional theory calculations CO oxidation single-atom catalyst graphyne dual-atom site catalyst

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Movement of Dirac points and band gaps in graphyne under rotating strain

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Nano Research 2017年第6期10卷 2005-2020页

作者： Zhenzhu Li Zhongfan Liu Zhirong Liu College of Chemistry and Molecular Engineering Center for Nanochemistry State Key Laboratory for Structure Chemistry of Unstableand Stable Species and Beijing National Laboratory for Molecular Sciences (BNLMS) Peking University Beijing 100871 China

The introduction of lattice anisotropy causes Dirac cones to shift in response to the applied strain, leaving a pseudogap at the original Dirac points. Here, a group-theory analysis is combined with first-principles calculations to reveal the movement characteristics of Dirac points and band gaps in various graphynes under rotating uniaxial and shear strains. Graphene, where linear effects dominate, is different from α-,β-, and γ-graphynes, which generate strong nonlinear responses due to their bendable acetylenic linkages. However, the linear components of the electronic response, which are essential in determining material performance such as intrinsic carrier mobility due to electron-phonon coupling, can be readily separated, and are well described by a unified theory. The movement of the Dirac points in α-graphyne is circular under a rotating strain, and the pseudogap opening is isotropic with a magnitude of only 2% that in graphene. In comparison, the movement in β-graphyne is elliptical and the center is displaced from the origin. For γ-graphyne, three branches of gaps change with the applied strains with a sine/cosine dependence on the strain angle. The developed methodology is useful in determining the electronic response to various strains of Dirac materials and two-dimensional semiconductors,

关键词： graphene graphyne Dirac point band gap first-principles strain effect

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The roles of electrons in the electronic structures and optical properties of graphyne

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Chinese Science Bulletin 2012年第23期57卷 3080-3085页

作者： HE XiuJie TAN Jie BU HongXia ZHANG HongYu ZHAO MingWen School of Physics and State Key Laboratory of Crystal Materials Shandong University Jinan 250100 China

The electronic structures and optical properties of graphyne consisting of sp-and sp 2-hybridized carbon atoms are studied using first-principles calculations.A tight-binding model of the 2p z orbitals are proposed to describe the electronic bands near the Fermi *** results show that the natural band gap of graphyne originates from the inhomogeneous bindings between differently-hybridized carbon *** interlayer interactions of bulk graphyne narrow the band gap to 0.16 eV and result in redshift of the optical spectral peaks as compared to single-layered graphyne.

关键词： graphyne electronic structure tight-binding model first—principles calculation

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Theory,preparation,properties and catalysis application in 2D graphynes-based materials

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Frontiers of physics 2021年第2期16卷 71-106页

作者： Ning Zhang Jiayu Wu Taoyuan Yu Jiaqi Lv He Liu Xiping Xu College of Photoelectrical Engineering Changchun University of Science and TechnologyChangchun 130022China

Carbon has three hybridization forms of sp^(-),sp^(2-)and sp^(3-),and the combination of diferent forms can obtain diferent kinds of carbon allotropes,such as diamond,carbon nanotubes,fullerene,graphynes(GYs)and graphdiyne(GDY).Among them,the GDY molecule is a single-layer two-dimensional(2D)planar structure material with highlyπ-conjugation formed by sp^(-)and sp^(2-)*** has a carbon atom ring composed of benzene ring and acetylene,which makes GDY have a uniformly distributed pore *** addition,GDY planar material have some slight wrinkles,which makes GDY have better self-stability than other 2D planar *** excellent properties of GDY make it attract the attention of ***,GDY is widely used in chemical catalysis,electronics,communications,clean energy and composite *** paper summarizes the recent progress of GDY research,including structure,preparation,properties and application of GDY in the field of catalysts.

关键词： 2D materials catalysis application graphyne property

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The rare two-dimensional materials with Dirac cones

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National Science Review 2015年第1期2卷 22-39页

作者： Jinying Wang Shibin Deng Zhongfan Liu Zhirong Liu Center for Nanochemstry Colledge of Chemistry and Molecular EngineeringPeking University

Inspired by the great development of graphene, more and more research has been conducted to seek new two-dimensional(2D) materials with Dirac cones. Although 2D Dirac materials possess many novel properties and physics, they are rare compared with the numerous 2D materials. To provide explanation for the rarity of 2D Dirac materials as well as clues in searching for new Dirac systems, here we review the recent theoretical aspects of various 2D Dirac materials, including graphene, silicene, germanene,graphynes, several boron and carbon sheets, transition-metal oxides(VO2)n/(TiO2)m and(CrO2)n/(TiO2)m, organic and organometallic crystals, so-MoS2, and artiicial latices(electron gases and ultracold atoms). heir structural and electronic properties are summarized. We also investigate how Dirac points emerge, move, and merge in these systems. he von Neumann–Wigner theorem is used to explain the scarcity of Dirac cones in 2D systems, which leads to rigorous requirements on the symmetry,parameters, Fermi level, and band overlap of materials to achieve Dirac cones. Connections between existence of Dirac cones and the structural features are also discussed.

关键词： graphene silicene graphyne two-dimensional Dirac cone Dirac materials

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