Síntese de catalisadores de Mo/TixZr1-x O2 obtidos pelo método dos precursores poliméricos e sua avaliação nas reações Sour Gas Shift (SGS) e redução catalítica seletiva com amônia (SCR-NH3).

Abstract

The objective of this study was to synthesize compounds Mo/TixZr1-xO2 catalytic materials, and its evaluation in Sour Gas Shift reactions and selective catalytic reduction with ammonia (SCR-NH3). The catalyst supports analyzed in this study were obtained from the polymeric precursor, followed by physical dispersion impregnation of metal molybdenum. The catalyst supports composition TixZr1-xO2, with (x = 0, 0.25, 0.5, 0.75 and 1 mol), were characterized by X ray diffraction, the adsorption/desorption N2 by the BET method and electron scanning microscopy. Patterns of X ray diffraction of pure and doped samples showed the formation of anatase and rutile phase of TiO2, as well as the formation of the tetragonal phase and monoclinic of ZrO2. The crystallite size and the value of surface area of all the compositions increased with increasing calcination temperature. However, as it increased the amount of dopant in a same temperature, it was observed that the doping hindered crystal growth. Morphological analysis of the samples showed that the agglomerates have a particle size distribution fairly uniform and irregularly shaped, without pre-sintering or porous structures. Finally, the catalyst showed that systems Mo/TixZr1-xO2 were not active for the reaction Sour Gas Shift (SGS), specifically in the removal of H2S in the stream of synthesis gas derived from natural gas. However, the same catalytic system is efficient in processes of selective catalytic reduction with ammonia (SCR-NH3), reaching levels close to 58% conversion.