摘要
The reduction of NO with ethanol on MoOb>3b>/Alb>2b>Ob>3b> and CeOb>2b>-ZrOb>2b>-supported Pd catalysts was studied. The Pd/CeOb>2b>-ZrOb>2b> sample showed higher activity for the conversion of NO and higher selectivity for Nb>2b> formation when compared to the Pd-MoOb>3b>/Alb>2b>Ob>3b> sample. The CO chemisorption results showed that the CeZr mixed oxide chemisorbed a higher amount of CO, and this is related to a higher reducibility capacity of this compound when compared to MoOb>3b>. Furthermore, TPD analysis of adsorbed NO and ethanol showed that the Pd/CeOb>2b>-ZrOb>2b> catalyst has a higher ability of dissociating NO to Nb>2b> and of decomposition of ethanol with the formation of COb>2b>. Also, TPSR experiments showed that on Pd-8Mo/Alb>2b>Ob>3b>, ethanol competes with NO for adsorption sites on partially reduced molybdenum oxide. This was not the case for the Pd/Ceb>0.75b>Zrb>0.25b>Ob>2b> catalyst, where both NO and ethanol adsorb and decompose on the partially reduced mixed oxide surface. These facts are probably related to the better performance of this catalyst in relation to the Pd-MoOb>3b>/Alb>2b>Ob>3b> catalyst for the NO + ethanol reaction.