Experimental and Theoretical Properties of MoS2+x Nanoplatelets

Abstract

The synthesis and the catalysis in the HDS of DBT reaction of nanostructured self-supported catalyst containing MoS2+x nanoplatelets have been investigated. Enhancement of higher activity observed in sulfide catalyst sample (d) with respect to the ex situ and in situ references is more closely related to the morphology change of particles (nanoplatelets). In this work, we suggest that certain structures present in model catalysts maybe related to low dimensional structures and present a theoretical study of two MoS2 clusters (one made of 34 atoms/cluster and the second one made of 41 atoms/cluster), to these clusters seven sulfur atoms were randomly located at the surface of the sulfur layer, in order to simulate certain structures resembling arrow shaped nanoplatelets that were found in a High Resolution TEM analysis performed in some MoS2 samples. Additionally, one of the goals is to enquire about the electronic properties presented in such structures when the clusters terminated as Moor S-edge and if it could be correlated to the catalyst behavior of these compounds. To the 34 atoms/cluster Mo-edge yielded metallic behavior while the second cluster the 41 atoms/ cluster S-edge yielded a semiconductor behavior with a forbidden energy gap Eg of the order of @ 3.6 eV between the Valence and Conductions bands respectively. Moreover, to the same clusters enunciated formerly, when the sulfur atoms were located at the surface of the S-layer, for the first cluster (34 atoms/cluster) yielded a more metallic behavior, while the second one (41 atoms/cluster) yielded an isolator behavior. Our results agree with the experimental and theoretical results presented by several groups in different laboratories arriving to the conclusion that the S-Mo-S Mo-edge arrow heads structures could be responsible to the enhancement of the catalytic activity on the MoS2 studied samples.

Share and Cite:

D. Galvan, A. Amarillas, N. Elizondo and M. José-Yacamán, "Experimental and Theoretical Properties of MoS2+x Nanoplatelets," Modern Research in Catalysis, Vol. 2 No. 4, 2013, pp. 164-171. doi: 10.4236/mrc.2013.24022.

Conflicts of Interest

The authors declare no conflicts of interest.

References

[1] M. V. Bollinger, J. V. Lauritsen, K. W. Jacobsen, J. K. Norstov, S. Helveg and F. Besenbacher, “One-Dimensional Metallic Edge States in MoS2,” Physical. Review Letters, Vol. 87, No. 19, 2001, Article ID: 196803.
http://dx.doi.org/10.1103/PhysRevLett.87.196803
[2] S. Helveg, J. V. Lauritsen, E. Lagsgaard, I. Stensgaard, J. K. Norskov, B. S. Clausen, H. Topsoe and F. Besenbacher, “Atomic-Scale Structure of Single Layer MoS2 Nanoclusters,” Physical Review Letters, Vol. 84, No. 5, 2000, pp. 951-954.
http://dx.doi.org/10.1103/PhysRevLett.84.951
[3] J. V. Lauritsen, S. Helveg, E. Lagsgaard, I. Stensgaard, B. S. Clausen, H. Topsoe and F. Besenbacher, “Atomic-Scale Structure of Co-Mo-S Nanostructures in Hydro treating Catalysis,” Journal Catalysis, Vol. 197, No. 1, 2001, pp. 1-5.
[4] J. V. Lauritsen, M. V. Bollinger, E. Laegsgaard, K. W. Jacobsen, J. K. Norskov, B. S. Clausen, H. Topsoe and F. Besenbacher, “Atomic-Scale Insight into Structure and Morphology Changes of MoS2,” Journal of Catalysis, Vol. 221, No. 2, 2004, pp. 510-522.
http://dx.doi.org/10.1016/j.jcat.2003.09.015
[5] J. V. Lauritsen, M. Nyberg, J. K. Norskov, B. S. Clausen, H. Topsoe, E. Laegsgaard and F. Besenbacher., “Hydrodesulfurization Reaction Pathways on MoS2 Nanoclusters,” Journal of Catalysis, Vol. 224, No. 1, 2004, pp. 94-106. http://dx.doi.org/10.1016/j.jcat.2004.02.009
[6] L. S. Byskov, J. K. Norskov, B. S. Clausen and H. Top-soe, “DFT Calculations of Unpromoted and Promoted MoS2-Based Hydrodesulfurization Catalysts,” Journal of Catalysis, Vol. 187, No. 1, 1999, pp. 109-122.
http://dx.doi.org/10.1006/jcat.1999.2598
[7] L. S. Byskov, J. K. Norskov, B. S. Clausen and H. Topsoe, “Edge Termination of MoS2 and CoMoS Catalyst Particles,” Catalysis Letters, Vol. 64, No. 2-4, 2000, pp. 95-99. http://dx.doi.org/10.1023/A:1019063709813
[8] H. Schweiger, P. Raybaud, G. Kresse and H. Toulhoat, “Shape and Edge State Modification of MoS2 Catalytic Nanoparticles Induced by Working Copnditions: A Theoretical Study,” Journal of. Cataysis, Vol.. 207, No. 1, 2002, pp. 76-87. http://dx.doi.org/10.1006/jcat.2002.3508
[9] A. Carlsson, M. Brorson and H. Topsfe, “Morphology of WS2 Nanoclusters in WS2/C Hydrodesulfurization Catalysts Revealed by High-Angle Annular Dark-Field Transmission Electron Microscopy (HAADF-STEM) Imaging,” Journal of Catalysis, Vol. 227, No. 2, 2004, pp. 530-536. http://dx.doi.org/10.1016/j.jcat.2004.08.031
[10] M. Egorova and R. Prins, “Hydrodesulfurization of Dibenzothiophene and 4,6-Dymethyldibenzothiophene over Sulfided NiMo/γ-Al2O3, CoMo/γ-Al2O3 and Mo/γ-Al2O3 Catalysts,” Journal of Catalysis, Vol. 225, No. 2, 2004, pp. 417-427. http://dx.doi.org/10.1016/j.jcat.2004.05.002
[11] M. Egorova and R. Prins. “Competitive Hydrodesulfurization of 4, 6 Dimethyldibenzothiophene, Hydrodinitrogenation of 2-Methylpyridine, and Hydrogenation of Naphtalene over Sulfided NiMo/γ-Al2O3,” Journal of Catalysis, Vol. 224, No. 2, 2004, pp. 278-287.
http://dx.doi.org/10.1016/j.jcat.2004.03.005
[12] F. Dumeignil, K. Sato, M. Imamura, N. Matsubayashi, E. Payen and H. Shimada, “Characterization and Hydrodesulfurization Activity of CoMo Catalyst Supported on Sol-gel Preparated Al2O3,” Applied Catalysis A: General, Vo. 287, No. 1, 2005, pp. 135-145.
[13] G. A. Camacho-Bragado, A. Olivas, S. Fuentes, D. H. Galvan and M. José-Yacamán, “Structure and Catalytic Properties of Nanostructured Molybdenum Sulfides,” Journal of Catalysis, Vol. 234, No. 1, 2005, pp. 182-190.
http://dx.doi.org/10.1016/j.jcat.2005.06.009
[14] T. P. Prasad, E. Diemann and A. Muller, “Thermal Decomposition of (NH4)2MoO2S2, (NH4)2WO2S2 and (NH4)2WS4,” Journal of Inorganic and Nuclear Chemistry, Vol. 35, No. 6, 1973, pp. 1895-1904.
http://dx.doi.org/10.1016/0022-1902(73)80124-1
[15] M.-H. Whangbo and R. Hoffmann, “The Band Structure of the Tetracyanoxilatinate Chain,” Journal of the American Chemical Society, Vol. 100, No. 19, 1978, pp. 6093-6098. http://dx.doi.org/10.1021/ja00487a020
[16] R. Hoffmann, “An Extended Hückel Theory of Hydrocarbons,” Journal of Chemical Physics, Vol. 39, No. 6, 1963, pp. 1397-1412.
http://dx.doi.org/10.1063/1.1734456
[17] G. A. Landrum, “F Orbitals Are Included in the Calculations as Version 3.0x, Using W. V. Glassey’s Routine.”
http://overlap.chem.Cornell.edu:8080/yaehmop.html
[18] W. V. Glassey, G. A. Papoian, R. Hoffmann, “Total Energy Partitioning within a One-electron Formalism: A Hamiltonean Population Study of Surface-CO Interaction in the C(2x2)-CO/Ni(100) Chemisorption System,” Journal of Chemical Physics, Vol. 111, No. 3, 1999, pp. 893-910.
[19] D. H. Galvan, “An Extended Hückel Calculation on Cubic Boron Nitride and Diamond,” Journal of Materials Science Letters, Vol. 17, No. 10, 1998, pp. 805-810.
http://dx.doi.org/10.1023/A:1006630320896
[20] P. D. Fleischauer, J. R. Lince, P. A. Bertrand, R. Baner, “Electronic Structure and Lubrication Properties of MoS2: A Qualitative Molecular Orbital Approach,” Langmuir, Vol. 5, No. 4, 1989, pp. 1009-1015.
http://dx.doi.org/10.1021/la00088a022
[21] S. Alvarez, “Tables of Parameters for Extended Huckel Calculations,” Universitat de Barcelona, Barcelon, 1993.
[22] E. Lifshin, “X-Ray Charactrization of Materials,” Wiley-VCH, Weinheim, Federal Republic of Germany, 1999, p. 74.
[23] D. D. Witehurst, T. Isoda and I. Mochida, “Present State of the Art and Future Challenges in the Hydrodesulfurization of Polyaromatic Sulfur Compounds,” Advanced Catalysis, Vol. 42, No. 4, 1998, pp. 345-471.
http://dx.doi.org/10.1016/S0360-0564(08)60631-8
[24] L. F. Mattheiss, “Band Structure of Transition-Metal-Cichalcogenides Layer Compounds,” Physical Review, Vol. 8, No. 8, 1973, pp. 3719-3740.
[25] A. J. Grand, T. M. Griffiths, G. D. Pitts and A. D. Yoffe, “The Electrical Properties and the Magnitude of the Indirect Gap in the Semiconducting Transition Metal Dichalcogenide Layer Crystals,” Journal of Physics C: Solid State Physics, Vol. 8, No. 1, 1975, p. L17.
[26] M. Sun, A. E. Nelson and J. Adjaye, “A DFT Study of WS2, NiWS and CoWS Hydrotreating Catalysts,” Journal of Catalysis, Vol. 226, No. 1, 2004, pp. 41-53.
http://dx.doi.org/10.1016/j.jcat.2004.04.023
[27] A. H. Reshak and S. Auluck, “Calculated Optical Properties of 2H-MoS2 Intercalated with Lithium,” Physical Review, Vol. 68, No. 12, 2003, Article ID: 125101.
[28] M. W. Wolfsberg and L. Helmholtz, “The Spectra and Electronic Structure of the Tetrahedral Ions , and ,” Journal of chemical Physics, Vol. 20, No. 5, 1952, pp. 837-843.

Copyright © 2024 by authors and Scientific Research Publishing Inc.

Creative Commons License

This work and the related PDF file are licensed under a Creative Commons Attribution 4.0 International License.