Efeito da dispersão metálica de Ni sobre a atividade de catalisadores Ni/NTC na reação de hidrodesoxigenação do bio-óleo (guaiacol) /

Abstract

Oils from liquefied biomass (also called bio-oils) contain a large amount of oxygenated compounds (GALDINO 2010). One of the most studied oxygen removal process is the Hydrodeoxygenation (HDO) reactions using a solid catalyst (FURINSKY 2000). Therefore, present study aimed to evaluate the metallic dispersion of Ni supported in carbon nanotubes and its performance as a catalyst in the reaction of HDO of the bio-oil (using guaiacol as a molecular model). Catalysts 2, 11 and, 20% Ni / NTC (mass%) were prepared. The determination of the physicochemical properties was performed by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), programmed temperature reduction (TPR), thermoprogrammed desorption in Helium flow (TP-He), N2 fisistion, chemical quantification by ICP-OES. Through the analysis of DRX, MET and MEV, it was verified that the increase of the Ni content decreased the metallic dispersion. The catalytic tests showed that the metallic dispersion influences the performance of the catalysts in the HDO reaction, since the TOF for the 2% Ni / NTC catalyst was almost twice as high as the observed TOF for 11% Ni / NTC, and three times greater than 20% Ni / NTC. However, in order to obtain fully deoxygenated products, the conversion needs to be high because up to 35% conversion only mono-oxygen intermediates were produced. The results obtained in this work may guide future work on the metallic particle size to be used and also the use of functionalized supports to improve the selectivity of the HDO reaction.