scholarly journals A New Class of Scandium Carbide Nanosheet

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Jing Wang ◽  
Tian-Tian Liu ◽  
Chen-Ling Li ◽  
Ying Liu

Abstract A new class of two-dimensional scandium carbide nanosheet has been identified by using first-principles density functional theory. It has a primitive cell of Sc3C10, in which there are two pentagonal carbon rings surrounded by one scandium octagon. Being as the precussor of Volleyballene Sc20C60 and ScC nanotubes, the Sc3C10 nanosheet is exceptionally stable. By rolling up this Sc3C10 sheet, a series of stable ScC nanotubes have been obtained. All the nanotubes studied have been found to be metallic. Furthermore, the hydrogen storage capacity of the ScC nanotubes has been explored. The calculated results show that one unit of the (0,3) ScC nanotube can adsorb a maximum of 51 hydrogen molecules, reaching up to a 6.25 wt% hydrogen gravimetric density with an average binding energy of 0.23 eV/H2.

2017 ◽  
Vol 17 ◽  
pp. 131-139 ◽  
Author(s):  
B. Rekha ◽  
S. Seenithurai ◽  
R. Kodi Pandyan ◽  
S. Vinodh Kumar ◽  
Manickam Mahendran

From first principles density functional theory, Li-decorated octagraphene and its usage as a hydrogen storage media is theoretically investigated. Octagraphene is a versatile structure with periodic sp2 – bonded carbon atomic planar sheet. This carbon allotrope consists of carbon octagons and rectangular lattices with two bond lengths. The Li binding energy in octagraphene is 2.5 eV, which is much higher than that of pristine graphene. Maximum of four hydrogen molecules can be adsorbed on Li decorated on one side of octagraphene and this leads to a gravimetric storage capacity of 2.4 wt% with an average adsorption binding energy of 0.35eV/H2. Li decorated on both sides of octagraphene, attains a gravimetric storage capacity of 8.1 wt% with an average binding energy of 0.23 eV/ H2. Thus, the structure investigated here is flattering for the reversible hydrogen adsorption/ desorption at the room temperature.


2017 ◽  
Author(s):  
Lyudmyla Adamska ◽  
Sridhar Sadasivam ◽  
Jonathan J. Foley ◽  
Pierre Darancet ◽  
Sahar Sharifzadeh

Two-dimensional boron is promising as a tunable monolayer metal for nano-optoelectronics. We study the optoelectronic properties of two likely allotropes of two-dimensional boron using first-principles density functional theory and many-body perturbation theory. We find that both systems are anisotropic metals, with strong energy- and thickness-dependent optical transparency and a weak (<1%) absorbance in the visible range. Additionally, using state-of-the-art methods for the description of the electron-phonon and electron-electron interactions, we show that the electrical conductivity is limited by electron-phonon interactions. Our results indicate that both structures are suitable as a transparent electrode.


2013 ◽  
Vol 677 ◽  
pp. 149-152
Author(s):  
Bo An ◽  
Hai Yan Zhu

The paper mainly focuses on the ability of absorbing hydrogen molecule of the dimetallocene (C5H5)2TM2(TM=Ti/Zn/Cu/Ni) based on the first-principles calculation. The result indicates that these compounds can adsorb up to eight hydrogen molecules, the binding energy is 0.596eV/H2 for Cp2Ti2, 0.802eV/H2 for Cp2Zn2, 0.422eV/H2 for Cp2Cu2 and 0.182eV/H2 for Cp2Ni2 respectively. The corresponding gravimetric hydrogen-storage capacity is 7.1wt% for Cp2Ti2, 6.2wt% for Cp2Zn2, 6.3wt% for Cp2Cu2 and 6.5wt% for Cp2Ni2 respectively. These sandwich-type organometallocenes proposed in this work are favorable for reversible adsorption and desorption of hydrogen under ambient conditions. These predictions will likely provide a new route for developing novel high-capacity hydrogen-storage materials.


Author(s):  
Amina Bouheddadj ◽  
Tarik Ouahrani ◽  
Gbèdodé Wilfried KANNHOUNON ◽  
Boufatah Reda ◽  
Sumeya Bedrane ◽  
...  

First-principles based on density functional theory (DFT) calculations were performed to investigate the interaction of two-dimensional (2D) HfS2 with SO2, a harmful gas with implications for climate change. In particular,...


Crystals ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 441 ◽  
Author(s):  
Nisha Geng ◽  
Tiange Bi ◽  
Niloofar Zarifi ◽  
Yan Yan ◽  
Eva Zurek

Interest in Na-S compounds stems from their use in battery materials at 1 atm, as well as the potential for superconductivity under pressure. Evolutionary structure searches coupled with Density Functional Theory calculations were employed to predict stable and low-lying metastable phases of sodium poor and sodium rich sulfides at 1 atm and within 100–200 GPa. At ambient pressures, four new stable or metastable phases with unbranched sulfur motifs were predicted: Na2S3 with C 2 / c and Imm2 symmetry, C 2 -Na2S5 and C 2 -Na2S8. Van der Waals interactions were shown to affect the energy ordering of various polymorphs. At high pressure, several novel phases that contained a wide variety of zero-, one-, and two-dimensional sulfur motifs were predicted, and their electronic structures and bonding were analyzed. At 200 GPa, P 4 / m m m -Na2S8 was predicted to become superconducting below 15.5 K, which is close to results previously obtained for the β -Po phase of elemental sulfur. The structures of the most stable M3S and M4S, M = Na, phases differed from those previously reported for compounds with M = H, Li, K.


2017 ◽  
Vol 31 (03) ◽  
pp. 1750017 ◽  
Author(s):  
Yan-Ni Wen ◽  
Peng-Fei Gao ◽  
Xi Chen ◽  
Ming-Gang Xia ◽  
Yang Zhang ◽  
...  

First-principles study based on density functional theory has been employed to investigate width-dependent structural stability and magnetic properties of monolayer zigzag MoS2 nanoribbons (ZZ-MoS2 NRs). The width N = 4–6 (the numbers of zigzag Mo–S chains along the ribbon length) are considered. The results show that all studied ZZ-MoS2 NRs are less stable than two-dimensional MoS2 monolayer, exhibiting that a broader width ribbon behaves better structural stability and an inversely proportional relationship between the structural stability (or the ribbon with) and boundary S–Mo interaction. Electronic states imply that all ZZ-MoS2 NRs exhibit magnetic properties, regardless of their widths. Total magnetic moment increases with the increasing width N, which is mainly ascribed to the decreasing S–Mo interaction of the two zigzag edges. In order to confirm this reason, a uniaxial tension strain is applied to ZZ-MoS2 NRs. It has been found that, with the increasing tension strain, the bond length of boundary S–Mo increases, at the same time, the magnetic moment increases also. Our results suggest the rational applications of ZZ-MoS2 NRs in nanoelectronics and spintronics.


RSC Advances ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 952-957 ◽  
Author(s):  
Konstantina Iordanidou ◽  
Michel Houssa ◽  
Clas Persson

Using first principles calculations based on density functional theory the impact of hole doping on the magnetic and electronic properties of two dimensional PtS2 is studied.


2017 ◽  
Vol 5 (10) ◽  
pp. 4912-4922 ◽  
Author(s):  
Kun-Han Lin ◽  
Chin-Lung Kuo

New findings on the lithiation mechanisms and the achievable Li capacity limits of various types of functional groups on the basal plane and those terminating the edge sites of graphene nanomaterials based on first-principles density functional theory calculations.


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