3R and 2H polytypes of MoS2: DFT and DFPT calculations of structural, optoelectronic, vibrational and thermodynamic properties

Coutinho, Samir S.; Tavares, M.S.; Barboza, C.A.; Frazão, Nilton Ferreira; Moreira, E.; Azevedo, David L.

doi:10.1016/j.jpcs.2017.07.010

Cited by 41 publications

(30 citation statements)

References 63 publications

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“…Theoretical studies, particularly those based on DFT calculations, have greatly contributed to the understanding of the physical/chemical properties of materials based on MoS 2 and their relationship with the experimentally observed properties. The theoretical results show that the bulk 2H-MoS 2 is a material that presents both direct and indirect band gaps with values very close to the experimentally reported [166][167][168], but also predict that the doping of this material with transition metals (or under pressure) could tailor their chemical, optical and electronic properties for the development of new interesting technological applications [169][170][171]. Also, a whole universe of possibilities arises with a reduction in dimensions of this kind of materials, which offers the possibilities of exploiting band-gap engineering [172][173][174][175][176][177][178][179][180] and of obtaining new magnetic properties [181][182][183].…”

Section: Theoretical Studiessupporting

confidence: 80%

Recent Insights in Transition Metal Sulfide Hydrodesulfurization Catalysts for the Production of Ultra Low Sulfur Diesel: A Short Review

et al. 2019

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The literature from the past few years dealing with hydrodesulfurization catalysts to deeply remove the sulfur-containing compounds in fuels is reviewed in this communication. We focus on the typical transition metal sulfides (TMS) Ni/Co-promoted Mo, W-based bi- and tri-metallic catalysts for selective removal of sulfur from typical refractory compounds. This review is separated into three very specific topics of the catalysts to produce ultra-low sulfur diesel. The first issue is the supported catalysts; the second, the self-supported or unsupported catalysts and finally, a brief discussion about the theoretical studies. We also inspect some details about the effect of support, the use of organic and inorganic additives and aspects related to the preparation of unsupported catalysts. We discuss some hot topics and details of the unsupported catalyst preparation that could influence the sulfur removal capacity of specific systems. Parameters such as surface acidity, dispersion, morphological changes of the active phases, and the promotion effect are the common factors discussed in the vast majority of present-day research. We conclude from this review that hydrodesulfurization performance of TMS catalysts supported or unsupported may be improved by using new methodologies, both experimental and theoretical, to fulfill the societal needs of ultra-low sulfur fuels, which more stringent future regulations will require.

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Section: Theoretical Studiessupporting

confidence: 80%

Recent Insights in Transition Metal Sulfide Hydrodesulfurization Catalysts for the Production of Ultra Low Sulfur Diesel: A Short Review

et al. 2019

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“…Density functional theory calculations were performed by using the local density approximation (LDA) as implemented in the AIMPRO code . LDA has been proved to give relatively good results for modelling the structure of bulk 2H‐MoS 2 (see Supplementary Information of) and 3R‐MoS 2 , and in structural and stability studies of periodic lattice distortions in single layer MoS 2 . Additionally, band structures of bulk 2H‐ and 3R‐MoS 2 and single‐ or few‐layer 2H‐MoS 2 , calculated using LDA, are similar to those calculated using GGA or the GW approximation (respectively), the main difference being an underestimation of LDA bandgaps.…”

Section: Methodsmentioning

confidence: 99%

“…LDA has been proved to give relatively good results for modelling the structure of bulk 2H‐MoS 2 (see Supplementary Information of) and 3R‐MoS 2 , and in structural and stability studies of periodic lattice distortions in single layer MoS 2 . Additionally, band structures of bulk 2H‐ and 3R‐MoS 2 and single‐ or few‐layer 2H‐MoS 2 , calculated using LDA, are similar to those calculated using GGA or the GW approximation (respectively), the main difference being an underestimation of LDA bandgaps. The spin‐averaged charge density is fitted to plane waves with an energy cut‐off of 100 Ha, while Kohn–Sham wave functions were constructed using localized Cartesian Gaussian orbital functions (50 for Mo, l ≤ 3, 28 for S, l ≤ 2).…”

Section: Methodsmentioning

confidence: 99%

Stability, Structure and Reconstruction of 1H‐Edges in MoS₂

Sayed‐Ahmad‐Baraza

Ewels

2020

Chemistry A European J

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Density functional studies of the edges of singlelayer 1H-MoS 2 are presented.T his phase presents ar ichv ariability of edges that can influencet he morphology and properties of MoS 2 nano-objects, play an important role in industrial chemical processes, and find future applications in energy storage, electronics and spintronics. The so-called Mo-100 %S edges vertical S-dimersw ere confirmedt ob e stable, however the authors also identified af amilyo fm etastable edges combining Mo atoms linked by two-electron donor symmetrical disulfide ligandsa nd four-electron donor unsymmetrical disulfide ligands. These may be entropically favored, potentially stabilizing them at high temperatures as a" liquid edge" phase. For Mo-50 %S edges, S-bridge structures with 3 periodicity along the edge are the most stable, compatible with aP eierls' distortion arising from the d-bands of the edge Mo atoms.A na dditional explanation for this periodicity is proposed through the formation of 3center bonds.Supporting information and the ORCID identification number(s) for the author(s) of this articlecan be found under: https://doi.

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“…The density of states of the conduction band is formed largely by d states from metal atoms (Mo or W), which agree with published data[161]. It could be noticed that c-band contains more metal states (dominated by Mod and Wd) than chalcogen states.…”

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confidence: 90%

Structure and electronic properties of 2D transition metal dichalcogenides : first principles study

Gusakova¹

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I would like to deeply thank my supervisor Prof. Tay Beng Kang for support and supervision, fruitful discussions and advices, patience, care and inspiration. I appreciate encouragement from Prof. Tay for me to attend conferences and to present my work, and linking me with experiment. I would like to thank my co-supervisor from BSUIR, Prof. Borisenko for your advice, suggestions and support before and during my PhD. I would like to thank Dr. Wang Xingli for our collaboration. I would like to thank Dr. Tan Chong Wei for all his help and for teaching me clean room basics. I would like to thank Mr. Soh Hwee Jin Melvin, Director of High Performance Computing Centre at NTU, for his help with any issues I have faced. Also I would like to thank all my lecturers from Belarusian State University,

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3R and 2H polytypes of MoS2: DFT and DFPT calculations of structural, optoelectronic, vibrational and thermodynamic properties

Cited by 41 publications

References 63 publications

Recent Insights in Transition Metal Sulfide Hydrodesulfurization Catalysts for the Production of Ultra Low Sulfur Diesel: A Short Review

Recent Insights in Transition Metal Sulfide Hydrodesulfurization Catalysts for the Production of Ultra Low Sulfur Diesel: A Short Review

Stability, Structure and Reconstruction of 1H‐Edges in MoS₂

Structure and electronic properties of 2D transition metal dichalcogenides : first principles study

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3R and 2H polytypes of MoS2: DFT and DFPT calculations of structural, optoelectronic, vibrational and thermodynamic properties

Cited by 41 publications

References 63 publications

Recent Insights in Transition Metal Sulfide Hydrodesulfurization Catalysts for the Production of Ultra Low Sulfur Diesel: A Short Review

Recent Insights in Transition Metal Sulfide Hydrodesulfurization Catalysts for the Production of Ultra Low Sulfur Diesel: A Short Review

Stability, Structure and Reconstruction of 1H‐Edges in MoS2

Structure and electronic properties of 2D transition metal dichalcogenides : first principles study

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Product

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Stability, Structure and Reconstruction of 1H‐Edges in MoS₂