Studies of MoS2 structures produced by electron irradiation

José–Yacamán, Miguel; Lopez, Hector; Santiago, P.; Galván, D. H.; Garzón, Ignacio L.; Reyes, A.

doi:10.1063/1.116932

Cited by 92 publications

(40 citation statements)

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“…A fase 1T é condutora 2 enquanto que as fases 2H e 3R são diamagnéticas e semicondutoras 3 . Além das três formas conhecidas de hábito cristalino, o dissulfeto de molibdênio se apresenta na forma amorfa 4,5 , como nanotubos 6,7 e esferas de dimensões nanoscópicas 7,8 semelhantes as estruturas dos fulerenos.…”

Section: Figura 1 Representação Esquemática Das Estrutura Das Fases unclassified

“…Além da obtenção do dissulfeto de molibdênio na forma de filmes finos orientados sobre vários substratos, recentemente observou-se que estes pode ser sintetizados na forma de nanotubos 6 e estruturas conhecidas como materiais inorgânicos semelhantes aos fulerenos 7,8 . Esses materiais apresentam as mesmas lamelas constituintes nos materiais bidimensionais porém com uma expansão das distâncias interplanares basais de cerca de 2% (6,2Å) em relação ao politipo 2H características observadas (6,15Å).…”

Section: Outras Estruturasunclassified

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Dissulfeto de molibdênio, um material multifuncional e surpreendente

Wypych

2002

Quím. Nova

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Recebido em 6/10/00; aceito em 4/4/01 MOLYBDENUM DISULFIDE, A MULTIFUNCTIONAL AND REMARKABLE MATERIAL. The aim of this work is to review the chemical and physical properties of layered molybdenum disulfide. The three polymorphic/polytypic modifications of the compound were found, the polytypes 2H (molybdenite) and 3R are semiconductors while the polymorph 1T is an electronic conductor. 2H-MoS 2 has several important industrial applications as hydrotreatment catalysts, energy storage devices, solar cells, solid lubricants, among others. When intercalated, the 2H phase changes to a distorted 1T phase, producing unstable intercalation compounds that can be exfoliated in solution, producing single layers and consequently nanocomposites. The direct synthesis of the 1T phase produces stable intercalation compounds. Recently molybdenum disulfide was prepared as nanotubes and fulerenelike structures that bring new insights in the investigation of this important material.Keywords: molybdenum disulfide; intercalation; layered materials. INTRODUÇÃOO dissulfeto de molibdênio pertence a uma classe de materiais conhecidos como compostos lamelares e ocorre em três modificações polimórficas/politípicas 1,2 . A fase mais comum (2H) ocorre na natureza na forma de molibdenita. Nas modificações 2H e 3R, áto-mos de molibdênio estão ligados covalentemente à átomos de enxofre numa geometria trigonal prismática regular (Figura 1). Os prismas trigonais estão ligados entre si pelas arestas, produzindo unidades bidimensionais conhecidas como lamelas. Essas lamelas que, estão conectadas por forças fracas do tipo Van der Waals, podem se ordenar de maneira diferente originando os dois politipos. Na fase 1T a forma ondulada se deve à distorção da esfera de coordenação octaédrica do centro metálico 2 . A forma do politipo 1T não distorcida está representada na Figura 1. Figura 1. Representação esquemática das estrutura das fases 2H, 3R e 1T (não distorcida), do dissulfeto de molibdênio.As propriedades dos politipos são diferentes. A fase 1T é condutora 2 enquanto que as fases 2H e 3R são diamagnéticas e semicondutoras 3. Além das três formas conhecidas de hábito cristalino, o dissulfeto de molibdênio se apresenta na forma amorfa 4,5 , como nanotubos 6,7 e esferas de dimensões nanoscópicas 7,8 semelhantes as estruturas dos fulerenos.As aplicações do dissulfeto de molibdênio vão desde baterias no estado sólido que utilizam meio não aquoso e íons lítio intercaláveis [9][10][11] , células solares 12 , como lubrificantes sólidos 13 , catalisadores [14][15][16][17][18] , onde desempenha um papel de importância fundamental, além de outras.Um dos processos de síntese do dissulfeto de molibdênio nas fases polimórficas 2H e 3R é a reação térmica direta entre o molibdênio metálico e enxofre elementar em ampolas de quartzo. Quando cristais grandes forem necessários utiliza-se o método de transporte de vapor químico com um halogeneto como o iodo como agente transportante 19 (Eq.1).Mo + 2 S ® MoS 2 + 2 I 2 « MoI 4 + S 2Nesse procedimento, quantidades estequ...

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Section: Figura 1 Representação Esquemática Das Estrutura Das Fases unclassified

Section: Outras Estruturasunclassified

Dissulfeto de molibdênio, um material multifuncional e surpreendente

Wypych

2002

Quím. Nova

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“…It was found, for example, Nano Res (2009) 2: 416 424 that such nanoparticles can serve as superior solid lubricants [20] and can improve the mechanical properties of various nanocomposites [21,22]. The synthetic methods employed to produce IF nanoparticles and INT can be divided roughly into two categories: (1) far from equilibrium processes such as laser ablation [23], arc discharge [14] and electron beam irradiation [3,24,25] and (2) chemical methods like chemical vapor transport [26] which operate in a regime closer to equilibrium and generate higher yields [27,28]. A successful scalingup for the synthesis of INT-WS 2 with a fl uidized bed reactor was recently reported [29].…”

Section: Introductionmentioning

confidence: 99%

Synthesis of WS2 and MoS2 fullerene-like nanoparticles from solid precursors

et al. 2009

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Inorganic fullerene-like WS 2 and MoS 2 nanoparticles have been synthesized using exclusively solid precursors, by reaction of the corresponding metal oxide nanopowder, sulfur and a hydrogen-releasing agent (NaBH 4 or LiAlH 4 ), achieved either by conventional furnace heating up to ~900 °C or by photothermal ablation at far higher temperatures driven by highly concentrated white light. In contrast to the established syntheses that require toxic and hazardous gases, working solely with solid precursors permits relatively safer reactor conditions conducive to industrial scale-up.

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“…The formation of inorganic fullerenes [3] from layered compounds like metal dichalcogenides MX 2 (M ϭ Mo, W; X ϭ S, Se) and their application in the field of tribology [4] generated further interest. There are several synthetic approaches such as gas-phase deposition [5,6], laser ablation [7,8], electron irradiation [9], and high-temperature chemical routes [10,11] for the synthesis of clusters. Nano forms of these materials have their own advantages over the corresponding bulk materials.…”

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Closed-cage clusters in the gaseous and condensed phases derived from sonochemically synthesized MoS₂ nanoflakes

Singh

Pradeep

Bhattacharjee

et al. 2007

J. Am. Soc. Mass Spectrom.

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The Mo 13 clusters we previously reported were derived from MoS 2 flakes prepared from bulk MoS 2 , although the nature of the precursor species was not fully understood. The existence of the clusters in the condensed phase was a question. Here we report the preparation of MoS 2 nanoflakes from elemental precursors using the sonochemical method and study the gas-phase clusters derived from them using mass spectrometry. Ultraviolet-visible (UV-vis) spectrum of the precursor is comparable to nano MoS 2 derived from bulk MoS 2 . High-resolution transmission electron microscopy (HRTEM) revealed the formation of nanoflakes of MoS 2 with 10-to 30-nm length and 3-to 5-nm thickness. Laser desorption ionization mass spectrometry (LDI-MS) confirmed the formation of Mo 13 clusters from this nanomaterial. Matrix-assisted laser desorption ionization mass spectrometry (MALDI-MS) points to the existence of Mo 13 clusters in the condensed phase. The clusters appear to be stable because they do not fragment in the mass spectrometer even at the highest laser intensity. Computational analysis based on generalized Wannier orbitals is used to understand bonding and stability of the clusters. These clusters are highly stable with a rich variety in terms of centricity and multiplicity of MoOMo There are several synthetic approaches such as gas-phase deposition [5,6], laser ablation [7,8], electron irradiation [9], and high-temperature chemical routes [10,11] for the synthesis of clusters. Nano forms of these materials have their own advantages over the corresponding bulk materials. Electrochemical deposition [12] and sonochemical routes [13,14] are some other methods adapted for the synthesis of nanostructured materials. Electrochemical methods result in the formation of nanomaterials as a film, whereas sonochemical methods produce free-standing nanoflakes of metal chalcogenides with controlled size.

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Studies of MoS2 structures produced by electron irradiation

Cited by 92 publications

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Dissulfeto de molibdênio, um material multifuncional e surpreendente

Dissulfeto de molibdênio, um material multifuncional e surpreendente

Synthesis of WS2 and MoS2 fullerene-like nanoparticles from solid precursors

Closed-cage clusters in the gaseous and condensed phases derived from sonochemically synthesized MoS₂ nanoflakes

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Studies of MoS2 structures produced by electron irradiation

Cited by 92 publications

References 0 publications

Dissulfeto de molibdênio, um material multifuncional e surpreendente

Dissulfeto de molibdênio, um material multifuncional e surpreendente

Synthesis of WS2 and MoS2 fullerene-like nanoparticles from solid precursors

Closed-cage clusters in the gaseous and condensed phases derived from sonochemically synthesized MoS2 nanoflakes

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Product

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Closed-cage clusters in the gaseous and condensed phases derived from sonochemically synthesized MoS₂ nanoflakes