X-ray absorption fine structure study of the atomic and electronic structure of molybdenum disulfide intercalation compounds with transition metals

Zubavichus, Yan V.; Slovokhotov, Yurii L.; Schilling, Paul J.; Tittsworth, R. C.; Golub, A. S.; Protzenko, G.A.; Novikov, Yu. N.

doi:10.1016/s0020-1693(98)00209-6

Cited by 40 publications

(33 citation statements)

References 24 publications

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“…These layers slowly discharge in the dispersion due to a reaction with water, which produces molecular hydrogen and OH À anions. Owing to a residual negative charge on the MoS 2 layers, the structural changes typical of LiMoS 2 are partially retained in MoS 2 single-layer dispersions and in some solid intercalated materials freshly prepared from them [91,92].…”

Section: Intercalation Exfoliation and Restackingmentioning

confidence: 99%

Synthetic approaches to the molybdenum sulfide materials

Afanasiev

2007

Comptes Rendus. Chimie

106

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Section: Intercalation Exfoliation and Restackingmentioning

confidence: 99%

Synthetic approaches to the molybdenum sulfide materials

Afanasiev

2007

Comptes Rendus. Chimie

106

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“…Através do método de esfoliação, além dos polímeros, uma série de compostos não diretamente intercaláveis, foram intercalados no dissulfeto de molibdênio derivado da fase 2H [53][54][55][56][57][58][59][60][61][62][63][64][65] .…”

Section: Nanocompósitosunclassified

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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“…[5][6][7][8][9] Molybdenum disulfide (MoS 2 ) has great technological importance as catalysts (for the petrochemical hydrotreatment process), electrodes, solid-state lubricants, and materials with unusual two-dimensional magnetic properties. 10 As it was recently understood, the use of single-layer MoS 2 dispersions allowed an extension of the nature of guests.…”

Section: Introductionmentioning

confidence: 99%

Structural, thermal, and tribological properties of intercalated polyoxymethylene/molybdenum disulfide nanocomposites

Wang

et al. 2008

J of Applied Polymer Sci

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Intercalated polyoxymethylene (POM)/molybdenum disulfide (MoS 2 ) nanocomposites were prepared by in situ intercalation/polymerization. The structures of the composites were characterized by means of powder X-ray diffraction (XRD) and transmission electron microscopy. The XRD pattern showed that the polymer was inserted into the MoS 2 galleries. The interlayer spacing of the intercalated phase increased from 6.15 to 11.18 Å . The thermal behavior of the composites was also investigated through thermogravimetric analysis. The results show that the heat resistance of the intercalated composites decreased slightly. The tribological behavior of POM/MoS 2 was investigated on an MQ-800 end-face tirbometer under dry friction. The worn surfaces were observed by scanning electron microscopy. The results show that POM/MoS 2 presented better friction reduction and wear resistance, especially under high load. The friction mechanism of the nanocomposites is also discussed in association with X-ray photoelectron spectroscopy.

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X-ray absorption fine structure study of the atomic and electronic structure of molybdenum disulfide intercalation compounds with transition metals

Cited by 40 publications

References 24 publications

Synthetic approaches to the molybdenum sulfide materials

Synthetic approaches to the molybdenum sulfide materials

Dissulfeto de molibdênio, um material multifuncional e surpreendente

Structural, thermal, and tribological properties of intercalated polyoxymethylene/molybdenum disulfide nanocomposites

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