Síntese de catalisadores de Cu/CeO2 para utilização na oxidação preferencial do CO (PROX).

Abstract

The aim of this work has been to synthesize cerium oxide catalysts doped with copper, type Cei-xCux02, and evaluate their performance in the preferential oxidation of CO reaction (PROX). The catalysts analyzed in this work were obtained through two different synthesis methods, combustion reaction and Pechini, without the need of performing a step of impregnation of the active catalytic species. Thus, by means of both synthesis methods mentioned, were obtained in a step synthesis single, catalysts with the composition Cei-xCux02, where the value x in copper took the following values: 0, 0.1, 0.2 , 0.3, 0.4 and 0.5 mol. All samples synthesized catalysts were submitted to different techniques of structural and physical characterizations, and catalytic evaluation, carried out specifically in the PROX reaction in bench scale. By means the method of synthesis of the combustion reaction was not possible to obtain structures single phase Ce02 for all samples of catalysts with compositions containing the presence of Cu as a dopant element. However, the catalysts synthesized by the Pechini method, containing Cu as element dopant with concentrations up to 0.2 mol, presented single phase structures composed by Ce02 . It was concluded that for the synthesis of catalysts with composition Cei-xCux02 are not required concentrations of Cu higher that 0.2 mol for the PROX reaction reach great percentage, both in relation to CO conversion and in relation to selectivity, this finding was observed for both synthesis methods used. However, the Pechini method was better for carrying to obtainment of catalysts with structural characteristics more easily controllable and with upper catalytic performance.