Desenvolvimento de novos materiais catalíticos à base de Mo suportado em sílica e carvão mesoporoso ordenados para reações hidrodeoxigenação

Abstract

The aim of this thesis was to develop new catalytic materials through the synthesis of mesoporous silica and carbon supports for Mo impregnation to study its catalytic performance in hydrodeoxygenation of gas-phase platform molecules, where it was tried to determine the influence of the catalyst, support and support/catalyst behavior under different reaction conditions. Mesoporous carbons were obtained using the silica materials as a template. The impregnation of molybdenum oxide (MoO3) was carried out by the incipient wetness impregnation to obtain an amount of 4 and 2 Mo atoms/nm² in the silica and carbon supports. Characterization was performed using several techniques such as X-Ray Diffraction (XRD), N2 physisorption, Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), by these techniques was possible to confirm the synthesis of the silica and carbon materials and the subsequent impregnation of the molybdenum oxide. The oxygen storage capacity (OSC) technique allowed investigating the effect of thermal pre-treatments on MoO3 and, from this, to understand the influence of these pre-treatments on the catalytic performance of these materials. In addition to the supported MoO3, catalytic tests were performed with in situ and ex situ carburized Mo2C. The materials were evaluated in the hydrodeoxygenation reactions of the phenol with reaction temperature of 300 ° C and different pretreatment temperatures for the MoO3 supported. All catalysts presented selectivities to deoxygenated products higher than 97%. The oxides supported on the mesoporous carbon replicates showed higher conversions than the oxide supported on the silica materials. The increase in pretreatment temperature positively influenced the conversion to deoxygenated products for the oxide supported on the silica templates and their replicates. Reactions using Mo2C showed higher conversion values (27%) to the values observed with MoO3 (~ 1.3 - 18.5%), but no significant influence of the media was observed.