Molybdenum Diselenide: Rhombohedral High Pressure-High Temperature Polymorph

Towle, Laird C.; Oberbeck, V. R.; Brown, Bruce E.; Stajdohar, Ralph E.

doi:10.1126/science.154.3751.895

Cited by 38 publications

(18 citation statements)

References 6 publications

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“…Figure S2 bi nt he Supporting Information shows the XRD patterns of the CoSe 2 /MoSe 2 heterostructures. [21] To further verify the chemical reaction of Co(OH) 2 and MoSe 2 ,s eparately prepared Co(OH) 2 and MoSe 2 nanosheets were mixed homogeneously at an atomic ratio of Co/Mo = 0.2, and then were annealed under the same conditions. 89-2002), respectively; [20] the peaks at 31.7 and 56.48 correspond to the (101) and (110) phases of hexagonal MoSe 2 (JCPDS no.…”

Section: Resultsmentioning

confidence: 99%

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CoSe₂/MoSe₂ Heterostructures with Enriched Water Adsorption/Dissociation Sites towards Enhanced Alkaline Hydrogen Evolution Reaction

Zhao

Rui

et al. 2018

Chemistry A European J

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Transition-metal dichalcogenides (TMDs) are promising electrocatalysts toward the hydrogen evolution reaction (HER) in acid media, but they show significantly inferior activity in alkaline media due to the extremely sluggish water dissociation kinetics. Herein, CoSe /MoSe heterostructures with CoSe quantum dots anchored on MoSe nanosheets are synthesized towards enhanced alkaline HER catalytic activity. The incorporation of CoSe is intended to construct additional water adsorption sites on the basal planes of MoSe to promote water dissociation. The CoSe /MoSe heterostructures show substantially enhanced activity over MoSe and CoSe in 1 m KOH. The optimal overpotential required to reach a current density of 10 mA cm is merely 218 mV, which is more than 100 mV greater than that of MoSe , which is by far the best performance demonstrated for precious-metal-free catalysts. Detailed analyses based on electrochemical testing demonstrate that the water adsorption and subsequent dissociation process is accelerated by CoSe species with rich edge sites; meanwhile, MoSe species provide sufficient active sites for the adsorption and combination of adsorbed hydrogen (H ). These results provide an effective strategy for developing earth-abundant catalysts with high activity for the alkaline HER, and are of great significance to promote the practical application of alkaline water electrolysis.

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Section: Resultsmentioning

confidence: 99%

“…72-1420), respectively. [21] To further verify the chemical reaction of Co(OH) 2 and MoSe 2 ,s eparately prepared Co(OH) 2 and MoSe 2 nanosheets were mixed homogeneously at an atomic ratio of Co/Mo = 0.2, and then were annealed under the same conditions. In this case, orthorhombic CoSe 2 (o-CoSe 2 ;JCPDS no.…”

Section: Resultsmentioning

confidence: 99%

CoSe₂/MoSe₂ Heterostructures with Enriched Water Adsorption/Dissociation Sites towards Enhanced Alkaline Hydrogen Evolution Reaction

Zhao

Rui

et al. 2018

Chemistry A European J

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“…In this way, the inversion symmetry which is broken in single-layer MoS 2 is restored in the bulk 2H-MoS 2 . In addition to stable 2H phase, another stable phase, so called 3R phase with space group R3m is also popular and can be synthesized by controlled ways 32 34 35 . Besides three-dimensional spirals of atomic layered MoS 2 by the way of growth, such as the CVD synthesis 35 , another popular way is the mechanical folding/stacking of single-layer MoS 2 28 36 .…”

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confidence: 99%

Modulation of electronic properties from stacking orders and spin-orbit coupling for 3R-type MoS2

Fan

Zheng

Kuo

et al. 2016

Sci Rep

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Two-dimensional crystals stacked by van der Waals coupling, such as twisted graphene and coupled graphene-BN layers with unusual phenomena have been a focus of research recently. As a typical representative, with the modulation of structural symmetry, stacking orders and spin-orbit coupling, transitional metal dichalcogenides have shown a lot of fascinating properties. Here we reveal the effect of stacking orders with spin-orbit coupling on the electronic properties of few-layer 3R-type MoS2 by first principles methods. We analyze the splitting of states at the top of valence band and the bottom of conduction band, following the change of stacking order. We find that regardless of stacking orders and layers’ number, the spin-up and spin-down channels are evidently separated and can be as a basis for the valley dependent spin polarization. With a model Hamiltonian about the layer’s coupling, the band splitting can be effectively analyzed by the coupling parameters. It is found that the stacking sequences, such as abc and abca, have the stronger nearest-neighbor coupling which imply the popular of periodic abc stacking sequence in natural growth of MoS2.

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“…From [5] Our data [12]). The file containing the information about the structure is deposited in the inorganic database ICSD No.…”

Section: New Compound Assementioning

confidence: 95%

Structural transformations in the As–Se system under high pressures and temperatures

Lityagina

Kulikova

Зибров

et al. 2015

Journal of Alloys and Compounds

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Molybdenum Diselenide: Rhombohedral High Pressure-High Temperature Polymorph

Abstract: A three-layered rhombohedral form of molybdenum diselenide has been produced by subjecting the normal two-layered hexagonal form to pressures of 40 kilobars and temperatures of 1500 degrees C. The new form is isostructural with rhombohedral molybdenum disulfide.

Cited by 38 publications

References 6 publications

CoSe₂/MoSe₂ Heterostructures with Enriched Water Adsorption/Dissociation Sites towards Enhanced Alkaline Hydrogen Evolution Reaction

CoSe₂/MoSe₂ Heterostructures with Enriched Water Adsorption/Dissociation Sites towards Enhanced Alkaline Hydrogen Evolution Reaction

Modulation of electronic properties from stacking orders and spin-orbit coupling for 3R-type MoS2

Structural transformations in the As–Se system under high pressures and temperatures

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Molybdenum Diselenide: Rhombohedral High Pressure-High Temperature Polymorph

Abstract: A three-layered rhombohedral form of molybdenum diselenide has been produced by subjecting the normal two-layered hexagonal form to pressures of 40 kilobars and temperatures of 1500 degrees C. The new form is isostructural with rhombohedral molybdenum disulfide.

Cited by 38 publications

References 6 publications

CoSe2/MoSe2 Heterostructures with Enriched Water Adsorption/Dissociation Sites towards Enhanced Alkaline Hydrogen Evolution Reaction

CoSe2/MoSe2 Heterostructures with Enriched Water Adsorption/Dissociation Sites towards Enhanced Alkaline Hydrogen Evolution Reaction

Modulation of electronic properties from stacking orders and spin-orbit coupling for 3R-type MoS2

Structural transformations in the As–Se system under high pressures and temperatures

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About

CoSe₂/MoSe₂ Heterostructures with Enriched Water Adsorption/Dissociation Sites towards Enhanced Alkaline Hydrogen Evolution Reaction

CoSe₂/MoSe₂ Heterostructures with Enriched Water Adsorption/Dissociation Sites towards Enhanced Alkaline Hydrogen Evolution Reaction