Structure, dynamical stability, and electronic properties of phases in<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mtext>TaS</mml:mtext><mml:mn>2</mml:mn></mml:msub></mml:math>from a high-level quantum mechanical calculation

Lazar, Petr; Martincová, Jana; Otyepka, Michal

doi:10.1103/physrevb.92.224104

Cited by 50 publications

(40 citation statements)

References 67 publications

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“…The optB86b‐vdW belongs to the family of functionals based on a non‐local van der Waals kernel . It succeeded in providing a balanced description of solid‐state properties, adsorption energies of molecules on graphene, or complex structural and thermodynamical properties of layered TaS 2 . The M06L functional, on the other hand, is a meta ‐GGA member of the heavily parametrized Minnesota group of functionals and should be suitable for transition metals, inorganic, and organometallic complexes .…”

Section: Resultsmentioning

confidence: 99%

Role of the Edge Properties in the Hydrogen Evolution Reaction on MoS₂

Lazar

Otyepka

2017

Chemistry A European J

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Molybdenum disulfide, in particular its edges, has attracted considerable attention as possible substitute for platinum catalysts in the hydrogen evolution reaction (HER). The complex nature of the reaction complicates its detailed experimental investigations, which are mostly indirect and sample dependent. Therefore, density functional theory calculations were employed to study how the properties of the MoS Mo-edge influence the thermodynamics of hydrogen adsorption onto the edge. The effect of the computational model (one-dimensional nanostripe), border symmetry imposed by its length, sulfur saturation of the edge, and dimensionality of the material are discussed. Hydrogen adsorption was found to depend critically on the coverage of extra sulfur at the Mo edge. The bare Mo-edge and fully sulfur-covered Mo-edge are catalytically inactive. The most favorable hydrogen binding towards HER was found for the Mo-edge covered by sulfur monomers. This edge provides hydrogen adsorption free energies positioned around -0.25 eV at up to 50 % hydrogen coverage, close to the experimental values of overpotential needed for the HER reaction.

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Section: Resultsmentioning

confidence: 99%

Role of the Edge Properties in the Hydrogen Evolution Reaction on MoS₂

Lazar

Otyepka

2017

Chemistry A European J

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“…The energy cutoff for the plane‐wave expansion was set to 350 eV. We used an optimized van der Waals functional, optB86b‐vdW, which proved to describe the structural properties of various TaS 2 phases, which included the commensurate charge‐density wave phase . We calculated the catalytic properties of 2H TaS 2 and 1T TaS 2 .…”

Section: Methodsmentioning

confidence: 99%

2H→1T Phase Engineering of Layered Tantalum Disulfides in Electrocatalysis: Oxygen Reduction Reaction

Mazánek

Pumera

Lazar

et al. 2017

Chemistry A European J

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Tremendous attention is currently being paid to renewable sources of energy. Transition-metal dichalcogenides (TMDs) have been intensively studied for their promising catalytic activities in the hydrogen evolution reaction (HER) and the oxygen reduction reaction (ORR). In this fundamental work, we explored the catalytic properties of TMD family members 2H TaS and 1T TaS . Our findings reveal that both polytypes exhibit poor HER performance, which is even more pronounced after electrochemical reduction/oxidation. Our experimental data show that 1T TaS has a lower overpotential at a current density of -10 mA cm , despite theoretical DFT calculations that indicated that the more favorable free energy of hydrogen adsorption should make "perfect" 2H TaS a better HER catalyst. Thorough characterization showed that the higher conductivity of 1T TaS and a slightly higher surface oxidation of 2H TaS explains this discrepancy. Moreover, changes in the catalytic activity after electrochemical treatment are addressed here. For the ORR in an alkaline environment, the electrochemical treatment led to an improvement in catalytic properties. With onset potentials similar to that of Pt/C catalysts, TaS was found to be an efficient catalyst for the ORR, rather than for proton reduction, in contrast to the behavior of Group 6 layered TMDs.

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“…The contraction may be isotropic or anisotropic depending upon the structure and bonding. The compounds ZrW2O8 [1][2][3][4], ScF3 [5][6][7][8][9][10] and Cd(CN)2 [11] are the few famous materials which show isotropic negative thermal expansion behaviour.Large number of compounds like LiAlSiO4 [12], Ag3Co(CN)6 [13], KMn[Ag(CN)2]3 [14], ZnAu2(CN)4 [15,16], MCN (M=Ag, Au, Cu) [17] show anisotropic thermal expansion, where one of the direction shows negative thermal expansion behaviour. These compounds consist of polyhedral units and NTE arise due tocooperative rotation and deformation of these polyhedral units which contract open spaces in the lattice [18].…”

Section: Introductionmentioning

confidence: 99%

Negative thermal expansion behavior in MZrF6(M=Ca,Mg,Sr) : Ab initio lattice dynamical stu

et al. 2018

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The thermal expansion behavior of metal fluorides can be tuned by choosing appropriate metal cation.We present ab-initio lattice dynamical studies on the metal fluorides (CaZrF6, MgZrF6 and SrZrF6) and identify the anharmonic phonon modes responsible for the negative thermal expansion in these materials. These phonons involve ZrF6 polyhedral rotational motion, which leads to large transverse amplitude of the vibrations of the fluorine atom in the Zr-F-Zr bond. The compounds with larger anisotropy in the thermal amplitude of the fluorine atoms show larger NTE behaviour. This has enabled to understand the large variation in thermal expansion behaviour of these compounds at high temperature. The calculations also predict decrease of the frequency of these anharmonic phonons with increasing temperature.PACS numbers: 63.20.-e, 65.40.-b

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Structure, dynamical stability, and electronic properties of phases inTaS2from a high-level quantum mechanical calculation

Cited by 50 publications

References 67 publications

Role of the Edge Properties in the Hydrogen Evolution Reaction on MoS₂

Role of the Edge Properties in the Hydrogen Evolution Reaction on MoS₂

2H→1T Phase Engineering of Layered Tantalum Disulfides in Electrocatalysis: Oxygen Reduction Reaction

Negative thermal expansion behavior in MZrF6(M=Ca,Mg,Sr) : Ab initio lattice dynamical stu

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Structure, dynamical stability, and electronic properties of phases inTaS2from a high-level quantum mechanical calculation

Cited by 50 publications

References 67 publications

Role of the Edge Properties in the Hydrogen Evolution Reaction on MoS2

Role of the Edge Properties in the Hydrogen Evolution Reaction on MoS2

2H→1T Phase Engineering of Layered Tantalum Disulfides in Electrocatalysis: Oxygen Reduction Reaction

Negative thermal expansion behavior in MZrF6(M=Ca,Mg,Sr) : Ab initio lattice dynamical stu

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Role of the Edge Properties in the Hydrogen Evolution Reaction on MoS₂

Role of the Edge Properties in the Hydrogen Evolution Reaction on MoS₂