Influence of ZrO2/Al2O3 Ratio in Carrier on Performance of Pt/ZrO2-Al2O3 Catalyst

Diesel engines have been more and more widely used in heavy duty vehicles because of high efficiency and low fuel consumption compared with petrol engines. Taking ZrO2 as the additive, the influence of the mass ratio of ZrO2 to Al2O3 on catalytic performance was studied. The results show that, with an increase of ZrO2 doping, the Pt particles become smaller at first and then larger in the catalyst. The interaction between Pt and the carrier increases, and then decreases. Analysis of the activity data shows the optimized doping amount of ZrO2 is 40 wt% the complete oxidation temperatures of CO and C3H6 are reduced by 20 and 25 oC, respectively. When the ZrO2/Al2O3 mass ratio in the carrier is varied, the precious metal dispersion on the catalyst and the precious metals interaction with the carrier are different with varying levels. The smaller the Pt particle size, the stronger the interaction between precious metal and the carrier, and the performance of catalyst is improved.