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Effect of the Pd on Pd-Mo/MCM-41 mesoporous catalysts in the hydrotreating of model molecules

Abstract:

Catalysts with molybdenum as active phase at 12% wt. promoted with palladium at 0, 1, 2 and 3% wt. supported on a mesoporous molecular sieves MCM-41 type were prepared by successive incipient impregnation. X-ray diffraction analysis showed that the mesoporous support presented a pattern of four reflections characteristic of the hexagonal structure of this material, while the catalysts showed the MoO3 orthorhombic and PdO tetragonal oxide phases. N2 physisorption isotherms showed that the support had a specific area of 920 m2/g and a type IV isotherm, typical of mesoporous materials. On the other hand, the catalysts presented lower specific surface areas and type IV isotherms that indicated the retention of the mesoporous nature. SEM images exhibited that the morphology of the parent MCM-4 was retained in all catalysts, and any other phases of the impregnated metals were not distinguished. All catalysts were active in the catalytic tests. 2%Pd-Mo/MCM-41 catalyst presented the best performance in all the reactions.