SUPPORT COMPOSITION EFFECT ON SUPERFICIAL STRUCTURES OF NICKEL AND MOLYBDENUM OXIDES SUPPORTED ON TiO2-Al2O3 MIXED OXIDES

  • G. Lozano-Hernández Universidad Autónoma del Estado de Hidalgo
  • E. M. Lozada-Ascencio Universidad Autónoma del Estado de Hidalgo
  • A. Guevara-Lara
Keywords: TiO2-Al2O3, raman, Uv-vis diffuse reflectance, ζ-Potential

Abstract

In order to synthesize new hydrodesulfurization catalysts with high dispersion of active sites, in this work it is presented a study of the effect of the support on superficial Ni-Mo-support interactions during impregnation process. TiO2-Al2O3 mixed oxides with 5, 10 and 90 % mol of Al2O3 were synthesized by the sol-gel method. Characterization of the support was performed by X-ray diffraction (XRD), ζ-potential and N2 physisorption. Ni and Mo superficial species were analyzed by UV-vis diffuse reflectance (UV-vis-DRS) and Raman spectroscopies, respectively. DRX results show that TiO2-Al2O3 mixed oxides present a gamma-alumina and amorphous-titania structures. The ζ-potential results show that the supports have surfaces with similar charges and net surface pH between 7-8. Raman spectroscopy shows that the net surface pH of support controls the symmetry of Mo oxide, which is octahedral, whereas MoO4 2-, Mo7O24 6- and Mo8O36 4- clusters distribution is controlled by Al2O3 concentration. The catalysts with high Al2O3 content show vibration modes due to Mo-O-Mo stretching, whereas the low Al2O3 content catalysts these modes are of the terminal Mo=Ot bond. UV-vis-DRS results show the coexistence of Ni2+ ion with tetrahedral [Ni2+4O2-] and octahedral [Ni2+6O2-] coordination. Catalysts with high contents of Al2O3 favor the tetrahedral Ni2+ ion that forms the Ni2+/γ-Al2O3 spinel. Catalysts with low contents of Al2O3 favor the octahedral Ni2+ ion, indicating a mayor interaction with octahedral Mo oxide species.

References

Araki, Y., Honna, K. y Shimada, H. (2002). Formation and Catalytic Properties of Edge-Bonded Molybdenum Sulfide Catalysts on TiO2. Journal of Catalysis 207, 361-370.

Carter, C.J., Khulbe, P.K., Gray, J., Van Zeec J.W. y Michel Angel, S. (2004). Raman spectroscopic evidence supporting the existence of Ni4(OH)4 4+ in aqueous, Ni(NO3)2 solutions. Analytica Chimica Acta 514, 241–245.

Chang, H. y Huang, P.J. (1998). Thermo-Raman Studies on Anatase and Rutile. Journal of Raman Spectroscopy 29, 97-102.

Coulier, L., van Veen, J.A.R. y Niemantsverdriet, J.W. (2002). TiO2-Supported Mo model catalysts: Ti as promoted for thiophene HDS? Catalysis Letters 79, 149-155.

Deo, G. y Wachs, I.E. (1991). Predicting Molecular Structures of Surface Metal Oxide Species on Oxide Supports under Ambient Conditions. Journal of Physical chemistry 95, 5889-5895.

Foger, K. y Anderson, J.R. (1986). Thermally stable SMSI supports: Iridium supported on TiO2-Al2O3 and Ce-stabilized Anatase. Applied Catalysis 23, 139-155.

Hensen, E.J.M., de Beer, V.H.J., van Veen, J. A. R. y van Santen, R.A. (2002). A refinement on the notion of type I and II (Co)MoS phases in hydrotreating catalysts. Catalysis Letters 84, 59-67.

Hu, H., Bare, S. R. y Wachs I.E. (1995). Surface Structures of Supported Molybdenum Oxide Catalysts: Characterization by Raman and Mo L3-Edge XANES. Journal of Physical Chemistry 99, 10897-10910.

Hunter, R.J. (1981). “ZETA POTENTIAL IN COLLOID SCIENCE: Principles and applications”. Editors R. H. Ottewill, R. L. Rowell “Colloid Science Series” of Academic Press, London.

Iova, F. y Trutia, A. (2000). On the structure of the NiO-Al2O3 systems, studied by diffuse-reflectance spectroscopy. Optical Materials 13,455-458.

Jacono, M.L., Sachiavello, M., Cimino, A. (1971). Structural, Magnetic, and Optical Properties of Nickel Oxide Supported on η- and γ-Aluminas. Journal of Physical Chemistry 75, 1044-1050.

JCPDS. (1993). Archivos de International Centre for Difraction Data. “Mineral Power Difraction File: JCPDS”,Pensylvania USA.

Jeziorowski, H. y Knözinger H. (1979). Raman and Ultraviolet Spectroscopic Characterization of Molybdena on Alumina Catalysts. Journal of Physical Chemistry 83, 1166-1173.

Kasztelan, S., Payen, E., Toulhoat, H., Grimblot, J. y Bonnelle, J.P. (1986). Industrial MoO3-Promoter Hydrotreating Catalysts: Genesis and architecture description. Polyhedron 5,167-167.

Kim, D.S., Segawa, K., Soeya, T. y Wachs, I.E. (1992). Surface structures of supported molybdenum oxide catalysts under ambient conditions. Journal of Catalysis 136, 539-553.

Lever, A.B. (1984). Inorganic Electronic Spectroscopy. 2nd edition. Studies in physical Theoretical Chemistry; Elsevier: Amsterdam, 507-711.

Li, Y.S., Lu, W. y Collins, W.E. (1991). Raman Spectroscopic Study on ZrO2-TiO2 Using MoO3 as a Molecular Probe. Journal of Raman Spectroscopy 22, 345-347.

Luthra, N.P. y Cheng, W-C. (1987). Molybdenum-95 NMR Study of the Adsorption of Molybdates on Alumina. Journal of Catalysis 107,154-160.

Ma, X., Sakanishi, K. y Mochida, I. (1994). Hydrodesulfurization reactivities of various sulfur compounds in diesel fuel. Industrial Engineering Chemical Research 33, 218-222.

Miller, J.M. y Lakshmi, L.J. (1988). Spectroscopic Characterization of Sol-Gel-Derived Mixed Oxides. Journal of Physic chemical B 102, 6465-6470.

Parks, A.G. (1965). The isoelectric point of solid oxides, solid hydroxides, and aqueous hidroxo complex systems. Chemical Reviews 65, 177-198.

Ramirez, J., Fuentes, S., Diaz, G., Vrinat, M., Breysse, M. y Lacroix, M. (1989). Hydrodesulphurization activity and characterization of sulphided molybdenum and cobalt— molybdenum catalysts: Comparison of Alumina-, Silica-Alumina- and Titania-Supported Catalysts. Applied Catalysis 52, 211-224.

Ramirez, J., Cuevas, R., Gasque, L., Vrinat, M. y Breysse, M. (1991). Promoting effect of fluorine on cobalt—molybdenum/titania hydrodesulfurization catalysts. Journal of Catalysis 71, 351-361.

Ramirez, J., Ruiz-Ramirez, L., Cedeno, L., Harle, V., Vrinat, M. y Breysse, M. (1993). Titania-alumina mixed oxides as supports for molybdenum hydrotreating catalysts. Applied Catalysis A: General 93, 163-180.

Sakashita, Y. (2001). Effects of surface orientation and crystallinity of alumina supports on microstructures of molybdenum oxides and sulfides. Surface Science 489, 45-58.

Schulz, H., Böhringer, W., Ousmanov, F. y Waller, P. (1999). Refractory sulfur compounds in gas oils. Fuel Processing Technology 61, 5-41.

Shimada, H. (2003). Morphology and orientation of MoS2 clusters on Al2O3 and TiO2 supports and their effect on catalytic performance. Catalysis Today 86, 17-29.

Stencel, J.M. (1990). Raman spectroscopy for Catalysis. Van Norstrand Reinhold Catalysis Series, USA.

Stranick, M.A., Houalla, M. and Hercules, D.M. (1990). Morphology and orientation of MoS2 clusters on Al2O3 and TiO2 supports and their effect on catalytic performance. Journal of Catalyisis 125, 214-226.

Topsøe, H., Clasusen, B.S. y Massot, F.E. (1996). “Hydrotreating Catalysis: Science and Technology”. Springer- Verlag Berlin Heidelberg. Vann Veen, J.A.R. y Hendriks, P.A.J.M. (1986). The adsorption of heptamolybdate ions on oxidic surfaces. Polyhedron 5, 75-78.

Wei, Z., Xin, Q. y Xiong, G. (1992). Investigation of the sulfidation of Mo/TiO2-Al2O3 catalysts by TPS and LRS. Catalysis Letters 15, 255-267.
Published
2020-09-03
How to Cite
Lozano-Hernández, G., Lozada-Ascencio, E. M., & Guevara-Lara, A. (2020). SUPPORT COMPOSITION EFFECT ON SUPERFICIAL STRUCTURES OF NICKEL AND MOLYBDENUM OXIDES SUPPORTED ON TiO2-Al2O3 MIXED OXIDES. Revista Mexicana De Ingeniería Química, 5(3), 311-320. Retrieved from http://www.rmiq.org/ojs311/index.php/rmiq/article/view/2008

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