Desenvolvimento de catalisadores de Ni/CeO2-ZrO2 com adição de promotores para produção de hidrogênio e/ou gás de síntese a partir da reação de reforma a vapor de álcoois

Abstract

AGRADECIMENTOSAcredito que sem Deus, sem família e sem pessoas amigas, nenhum trabalho é possível, por isso tenho muito que agradecer: ICP -Madri: Juanma, Rosa, Cristina, a doce Gema, Gofuen, Bárbara, Noelia Alf, Inma, Maria José, Ana Carolina, Maria José (La Wapi!), Silvia, Patri, Maricarmém, Javi, Fran, Aldossari, Beatriz Poceiro, Beatriz Arredondo, Paco CO(g) + 3H2(g) ↔ CH4(g) + H2O(g) Reação 13 ABSTRACTThe growing interest for alternative energy sources has stimulated the interest in the use of hydrogen and syngas obtained from renewable sources. Among these sources, the use of ethanol produced in Brazil from sugar cane and with a supply network already developed, and glycerol obtained as a byproduct in the biodiesel production have been highlighted in the last years.Hydrogen and syngas can be produced from steam reforming of ethanol and glycerol reactions (SRE and SRG), leading to a growing interest in the development of efficient catalysts for the production of H 2 and syngas from these alcohols.In the present thesis, catalysts of nickel supported on Ce x Zr 1-x O 2 solid solution were studied, with the goal of evaluating the performance of those in the SRE and SRG reactions.The supports were prepared by Pechini method and the catalysts were synthesized by impregnation and polymerization method in one step, with nickel loads of 5 wt.%, 10 wt.% and 15 wt.%. On the catalyst with better catalytic performance, it was impregnated 1wt% of Rh, Ru, Pt or Au as promoter.Supports and catalysts were characterized by X-ray diffraction (XRD), Raman spectroscopy, temperature-programmed reduction (TPR), oxygen storage capacity (OSC), N 2 physisorption (B.E.T. method), Diffuse Reflectance Infrared Spectroscopy with CO (DRIFTS -CO), X-ray absorption near edge structure (XANES -TPR H 2 ), X-ray photoelectron spectroscopy (XPS), energy dispersive X-ray spectroscopy (EDX) and Scanning electron microscopy (SEM).The catalytic tests of SRG were performed at 600 and 700 o C and for SRE at the tests were carried out at 400, 500 and 600 o C. The feed of water:alcohol was in the molar ratio of 3:1. DRIFTS coupled to a mass spectrometer analyzes was also carried out to identify the intermediates formed during the SRE. From the catalytic tests it was possible to observe that the support composition, metal load and preparation method influenced the selectivity to gaseous products, probably due to structural changes caused, mainly in the dispersion of the active phase on the support. Also, it was observed that the addition of noble metals favored a lower carbon deposition on the catalysts.