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e Atomic arrangements of different numbers of Li atoms adsorbed on GY and their corresponding average adsorption energy. The purple balls and red balls represent Li atoms adsorbed on the up-side and the back-side of GY, respectively. (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article.)
Source publication
Based on ab initio calculations, we investigated the hydrogen storage capacity of Li decorated 6,6,12-graphyne (Li@GY). Due to the unique sp hybridization in GY, Li atoms can strongly bind to carbon atoms to avoid the formation of Li clusters on the surface of GY. It is found that the hydrogen storage capacity of Li@GY is high up to 19.3 wt% with t...
Contexts in source publication
Context 1
... The Mulliken charge analysis shows that the Li at SA site donated 0.44 e to the substrate while the donation electron is only 0.23 e for Li at TA site. Moreover, the hollow space of SA ring is so large that the Li atom stay at the same plane of carbon atom in 6,6,12-GY. The binding strength for Li located at top of TA site is À1.59 eV as shown in Fig. 2(a). From Fig. 2, we found the average binding strength decrease as the number of Li atom increase. The binding strength remains negative value which means the binding strength is strong enough to prevent Li atoms from ...
Context 2
... binding strength for Li located at top of TA site is À1.59 eV as shown in Fig. 2(a). From Fig. 2, we found the average binding strength decrease as the number of Li atom increase. The binding strength remains negative value which means the binding strength is strong enough to prevent Li atoms from clustering. ...
Citations
... In the realm of all-carbon chemistry, the introduction of acetylene bonds markedly diversifies carbon isomers, encompassing graphyne and its derivatives [1][2][3][4][5]. Acetylene groups can lower bonding energy and modulate optical, thermal, and electronic properties in various ways [6][7][8][9]. These materials also manifest exceptional elasticity, adjustable Poisson's ratio [10], high fracture toughness, and impressive strength. ...
The 8-16-4 graphyne, a recently identified two-dimensional carbon allotrope, exhibits distinctive mechanical and electrical properties, making it a candidate material for flexible electronic applications. This study endeavors to enhance our comprehension of the fracture behavior and mechanical properties of 8-16-4 graphyne. The mechanical properties of 8-16-4 graphyne were evaluated through molecular dynamics simulations, examining the impact of boundary conditions, temperature, and strain rate, as well as the coupled interactions between temperature, vacancy defects, and microcracks. The findings reveal that 8-16-4 graphyne undergoes fracture via the cleavage of ethylene bonds at a critical strain value of approximately 0.29. Variations in boundary conditions and strain rate influence the fidelity of tensile simulation outcomes. Temperature, vacancy concentration, and the presence of microcracks markedly affect the mechanical properties of 8-16-4 graphyne. In contrast to other carbon allotropes, 8-16-4 graphyne exhibits a diminished sensitivity to vacancy defects in its mechanical performance. However, carbon vacancies at particular sites are more prone to initiating cracks. Furthermore, pre-existing microcracks within the material can potentially alter the fracture mode.
... Hence, researchers have proposed decorating graphene with suitable elements to enhance hydrogen adsorption. Carbon allotropes decorated with transition metals (Sc, Ti, V, Pd, Pt), alkali (Li, Na, K), and alkaline earth elements (Be, Mg, Ca) have been suggested as highly prospective materials for hydrogen storage [13][14][15][16][17][18][19][20][21][22][23][24]. Even though transition metal decoration improves adsorption energy, it has some drawbacks, such as metal aggregation and clustering, leading to reduced hydrogen atom or molecule adsorption [23][24][25]. ...
One-dimensional (1D) Tetra-Penta-Hepta graphene nanoribbon (TPH-GNR) is an enticing material because of its distinctive structural and electrical characteristics. Using first-principles calculations, we investigate hydrogen molecules (H 2) storage on alkali metal (M = Li and Na)-decorated TPH-GNR. The initial results indicate that the adsorption of H 2 on pristine TPH-GNR is weak (− 0.09 eV/H 2). However, alkali metal decoration significantly enhances the adsorption strength. Ab initio molecular dynamics simulations confirm the thermal stability of alkali metal-decorated TPH-GNR. We further analyze the charge transfer mechanism and density of states, which reveal a strong polarization of the H 2 molecules. Our study also reveals that 4 M@TPH-GNR exhibits gravimetric densities of 7.75 % (Li) and 6.90 % (Na), indicating the potential of TPH-GNR as an effective substrate for H 2 storage. Furthermore, a thermodynamic evaluation is conducted to examine the absorption and release of H 2 under practical operating conditions. Our findings suggest that alkali metal-decorated TPH-GNR can serve as a prospective material for efficient H 2 storage.
... The ionization of Li is important for subsequent H 2 adsorption through electrostatic interaction. As shown in This phenomenon was also found in previous works [57,58]. From figure 9(a), the orbital hybridizations were mainly from the N-p and B-p orbitals in B 4 N sheet. ...
The hydrogen storage performance of Li functionalized B4N re-entrant honeycomb monolayer is investigated by using density functional theory calculations. The calculated results indicate that dispersed Li atoms can strongly bond with two N atoms with a large average binding energy. It is found that each Li atom on B4N monolayer can capture up to four H2 molecules with a desirable average adsorption energy of 0.16 eV/H2. In the fully loaded case, forming B32N8Li4–16H2 compounds, the hydrogen storage density is up to 6.23 wt%. Ab initio molecular dynamics results manifest that Li-decorated B4N has a good reversible adsorption performance on H2 molecules. The Bader charge and density of states analysis demonstrates that hydrogen molecules are physically adsorbed on the Li atoms via the electrostatic interactions. These findings suggest that Li decorated B4N monolayer can be a very potential hydrogen storage material.
... Besides, the Li decorated γgraphyne has been found to be a potential hydrogen storage material, beacuse each Li atom can hold four hydrogen molecules [32]. For 6,6, 12-graphyne, the binding strength of Li is strong enough to prevent the formation of Li cluster on 6,6,12-graphyne surface, and the method of Li decorating can further enhance the hydrogen adsorption performance of 6,6,12-graphyne [33]. However, studies on the electron transport properties of Li decorated 6,6,12-graphyne are hitherto still lacking. ...
... In this work, we present a systematic investigation on the electron transport properties of Li decorated 6,6,12-graphyne in different transport directions by first-principles calculation. Based on the previous studies [33], there are only two stable structures are considered. We find that Li decorating can improve the electron transport performance and significantly enhance the NDR effect of 6,6,12-graphyne. ...
... Thus one TA ring can introduce two Li atoms one above the other. Among these Li decorated configurations, only two stable cases are considered [33]: introducing a Li atom into the SA ring in a single primitive cell, which is the most stable case named as PL1, as shown in the Fig. 1(b), and introducing a Li atom into the TA ring in a single primitive cell, named as PL2, as shown in the Fig. 1(c). ...
6,6,12-graphyne is found to be promising electronic materials in the field of nanoelectronic device. Previous studies have found that the 6,6,12-graphyne shows anisotropic current and negative differential resistance (NDR) and lithium (Li) decorated 6,6,12-graphyne has been found to be a potential hydrogen storage material. Herein, the electronic transport properties of Li decorated monolayer 6,6,12-graphyne are investigated via non-equilibrium Green’s function and the density functional theory. Compared with pristine 6,6,12-graphyne, our results demonstrate that Li enhances electronic transport properties of monolayer 6,6,12-graphyne. In details, the band structure and density of states of Li decorated 6,6,12-graphyne move toward the low energy region clearly, and the energy bands transform from zero band gap semiconductor to metallic properties after Li decorating. In addition, the corresponding two-electrode device models also exhibit anisotropy in electron transport. Remarkably, the current response in low bias region is significantly enhanced about one order of magnitude. Moreover, the NDR effect of Li decorated 6,6,12-graphyne is significantly enhanced and the NDR effect of zigzag models is more remarkable. This work demonstrates the electronic transport properties of Li decorated 6,6,12-graphyne, which can be further applied for novel nanoelectronic devices based on monolayer 6,6,12-graphyne.
... Moreover, based on different combinations of -C ---C-with the C-C bond in graphene network, α-, β-, γ-and 6, 6, 12-graphyne are formed with different electronic properties [27][28][29][30]. In contrast to the α, β, and 6, 6, 12-graphyne which are zero-band gap materials [28,29], the γ-graphyne (γ-GY) is a semiconductor with a bandgap of ~0.5 eV, making it as a favorable material in future nanoelectronics [29][30][31][32][33][34][35][36][37][38][39][40][41][42][43][44]. However, the weak adsorption of CO 2 , CO, NH 3 , NO, HN 3 and CH 4 on the pristine GY prevents its use in the gas sensor field [40,41,47,48]. ...
In the present theoretical study, the effect of methane adsorption on the electronic properties of titanium (Ti)-decorated γ-graphyne (γ-GY) is investigated. To this end, the dispersion-corrected density functional theory (DFT-D2) is employed to explicitly include the van der Waals interactions (vdW) in the computations. The results show that the methane is physisorbed on the γ‒GY owing to the low binding energy and relatively long adsorption distance. According to our calculations, Ti atom is chemically bound to four sp carbon atoms with the binding energy of −4.960 eV (per supercell) and provide an appropriate adsorption site for reducing gas molecule such as methane. We also observe that the methane molecule chemisorbed on the Ti-decorated γ-GY with the binding energy of −0.594 eV per supercell. Moreover, upon methane adsorption, the electronic bandgap of Ti-decorated γ-GY reduces about 0.051 eV. Our results reveal that Ti-decorated γ-GY has excellent sensing efficiency for CH4 gas with high selectivity and fast recovery time. Therefore, the present work encourages the growing use of Ti-decorated γ-GY for the development of thermopower-based, resistive-based, or quartz crystal microbalances-based methane sensors.
... The classical molecular dynamic simulation anticipated that GY nanosurface is entirely steady even when the temperature reached up to 1000 K. 35 These properties make GY as an important material for catalysis, energy storage, and some other applications. Theoretical studies anticipated that GY-supported single metal atoms such as Na, 36 Li,37,38 Ca, 39,40 and Ti 41 are good hydrogen storage mediums. Wu et al. studied that the single atom of Fe strongly bonded over the GY nanosheet shows a high catalytic activity toward CO oxidation. ...
Catalytic mechanisms and bonding analysis of NO oxidation and reduction on Cr single-atom catalysts (SACs) dispersed on graphyne (GY) surface have been systematically investigated using the first-principles theoretical methods. GY is a decent support for isolated transition metal (TM) atom catalysts because the most active sp hybridized carbon atoms exist on the GY surface. All the single TM atoms are trapped into the void of GY surface and existed in the isolated form. The molecular geometries and adsorbate binding energies of [email protected], [email protected] and [email protected] configurations are determined. We find that the Cr-GY is a most promising SAC for NO oxidation and reduction compared with the other TM-SACs. Herein, we report an efficient NO oxidation and reduction catalyzed by Cr-GY at ambient temperature. We find that Cr-GY SACs very reactive for NO oxidation and reduction at ambient temperature with low activation barriers to the rate determining steps for Eley-Rideal (ER) (0.87eV, 0.60eV & 0.62eV) and Langmuir-Hinshelwood (LH) (0.69eV, 0.62eV & 0.84eV) mechanisms. TER mechanism for the formation of NO2 molecule is not thermodynamically favorable. Comparative analysis revealed that the NO reduction (0.62eV) is more favorable than NO oxidation (0.84eV). These findings provide valuable perceptions for design of highly efficient and selective heterogeneous SACs for NO oxidation and reduction with transition metals.
... Subsequently, experimental reports on the synthesis of graphyne and graphyne-4 in the experiment, which fully demonstrated the excellent editability and diverse geometry of graphyne [5,[8][9][10]. At the same time, the research about the application of charge mobility of graphyne [11,12], mechanical properties [13,14], nanobelt characteristics [15][16][17], and electrodes in lithium batteries [18,19], hydrogen storage and lithium storage [20][21][22][23][24][25][26], and gas separation [27] are also about emerge. Graphyne has the natural advantage of being able to perform a large number of preparations at low temperatures and achieve the control of the planar pore size, making up for some of the natural defects of conventional carbon materials. ...
Based on the first-principles of density functional theory, this paper systematically studied the effect of tensile and compression deformation on the electrical properties of graphyne. The study show that the graphyne has an direct and adjustable band gap under deformation. Under uniaxial deformation, the band gap tend to be in the decline with the increase of the deformation, but under biaxial deformation, the band gap is positively correlated with the deformation, which increases with the rising of the tension deformation, and decreases with the increase of the compression deformation. The band gap value calculated by the HSE06 method is larger than what is obtained by the GGA method, but the shape characteristics of the band structure obtained by the two are basically the same, as well as the same trend between band gap and strain. With the tensile and compressive deformations increase, the charge transfer between C atoms in the graphyne is intensified. Compressive deformation makes the graphyne system more stable, while tensile deformation reduces the stability of graphyne. Compared with uniaxial, biaxial deformation has a more severe effect on the stability and band gap of the graphyne system, but less on charge transfer.
... Compared with graphene, 6,6,12-graphyne possesses smaller carrier effective mass, higher carrier mobility [23], and better hydrogen storage property [24]. In contrast to the electronic behavior studies of distorted or defected graphene nanoribbons [25,26] and nanotubes [27], heat conduction of graphyne nanoribbons with vacancy defects [28] and electronic conduction of various graphyne nanoribbons [21] have been reported. ...
The electronic transport properties of boron and nitrogen (B–N) pair co-doped 6,6,12-graphyne have been investigated comprehensively by means of the density functional theory combined with the non-equilibrium Green’s function method. In previous studies, the 6,6,12-graphyne represents a small carrier effective mass and high carrier mobility, and its limit in electronic application caused by the closed band gap can be broken through by B–N pair co-doping. It is found that the B–N pair co-doped 6,6,12-graphyne exhibits anisotropic current. The current along the armchair direction is much stronger than that in the zigzag direction. Intriguingly, the current–voltage characteristics generically exhibit a negative differential resistance effect, regardless of the B–N pair doping conformations. In addition, a current rectification effect is observed in the two-probe device models based on the B–N pair co-doped 6,6,12-graphyne. Our results reveal that both the current and rectification effect are intimately connected with the transmission peaks appearing near the Fermi level. These findings suggest that the B–N pair co-doped 6,6,12-graphyne is a promising material for microelectronic device design.
... It has non-zero band gap due to the presence of the acetylenic linkages and non-uniform π bindings [16]. There are several technological applications for these systems such as nanoelectronics [17][18][19], optoelectronics [20,21] hydrogen storage [22][23][24][25], electrode in batteries [26,27], gas sensor [28][29][30], gas separation [31], water desalination [32] and energy storage [33]. Unfortunately, some properties of pristine carbon structures are directly unsuitable for using in various purposes and must be manipulated. ...
In this work, electronic and structural properties of single Al or N atom doped and Al-N co-doped graphyne (GY) toward hydrogen storage were investigated using DFT-D calculations. Results show that N and Al atoms energetically prefer to lie instead of Csp in the chain and Csp2 in the hexagonal ring, respectively. Al or N doping changes conducting nature of GY from semiconductor to metallic. Pristine GY and more stable structures of Al doped, N doped and Al-N co-doped GY were examined for H2 adsorption. Adsorption energies for the first H2 molecule are about −0.140, −0.224, −0.141 and −0.288 eV/H2, respectively. They can hold 4, 9, 7 and 16 H2 molecules with average adsorption energy of ~−0.089, −0.158, −0.144 and −0.161 eV/H2, respectively. Also, the calculated corresponding hydrogen storage capacities reach up to 5.26, 10.17, 8.75 and 16.67 wt%, respectively. Although, effect of Al atom is more than N atom, when both of them co-doped in GY, its electronic and structural properties, as well as hydrogen storage capacity improve, extremely and they have a synergistic effect onto hydrogen adsorption. These findings show that N-Al co-doped GY can be used for designing new hydrogen storage materials in the future.
... Its alkyne ring with C sp2 -C sp and C sp -C sp bonds endows it with outstanding properties, including uniformly distributed pores, tunable electronic properties, structural flexibility, large surface area, and excellent electronic conductivity [22]. For example, the GY supported single Fe or Co atoms are found to be promising cathode catalysts of the fuel cell by first-principles calculations [23] and the GY supported single Ca [24,25], Li [26][27][28], and Ti [29] have been theoretically predicted to be good hydrogen storage mediums. In the sensing study, Si doped GY has a shorter recovery time in detecting NH 3 molecules than Ni doped GY [30]. ...
As one of the prominent applications in intelligent systems, gas sensing technology has attracted great interest in both industry and academia. In the current study, the pristine graphyne (GY) without and with a single Mn atom is investigated to detect the gas molecules (CO, CH4, CO2, NH3, NO and O2). The pristine GY is promising to detect O2 molecules because of its chemical adsorption on GY with large electron transfer. The great stability of the Mn/GY is found, and the Mn atom prefers to anchor at the alkyne ring as a single atom. Upon single Mn atom anchoring, the sensitivity and selectivity of GY based gas sensors is significantly improved for various molecules, except CH4. The recovery time of the Mn/GY after detecting the gas molecules may help to appraise the detection efficiency for the Mn/GY. The current study will help to understand the mechanism of detecting the gas molecules, and extend the potentially fascinating applications of GY-based materials.
