The role of Pd-Pt Interactions in the Oxidation and Sulfur Resistance of Bimetallic Pd-Pt/γ-Al2O3 Diesel Oxidation Catalysts

Diesel oxidation catalysts (DOC) were investigated for oxidation activity, NO conversion stability, and sulfur poisoning/regeneration on Pd/Al2O3, Pt/Al2O3, and Pd-Pt/Al2O3 catalysts. The Pd/Al2O3 catalyst was more active for CO and hydrocarbon (C3H6 and C3H8) oxidation, while the Pt/Al2O3 catalyst efficiently oxidized NO. The formation of a Pd-Pt alloy in the Pd-Pt/AAl(2)O(3) catalyst maintained Pd in a more reduced phase, resulting in the superior activity of this catalyst for the oxidation of CO, C3H6, and NO in comparison with its monometallic counterparts. The Pd-Pt alloy not only provided more low-temperature activity but also retained the stability of NO oxidation. The Pd-Pt alloy also favored the spillover of SO2 to the alumina support, resulting in significantly higher adsorption capacity of the Pd-Pt/Al2O3 catalyst, extensively prolonging its lifetime. However, the stable sulfates on Pd-Pt/Al2O3 made it difficult to completely regenerate the catalyst. The bimetallic sample showed higher activity for CO, C3H8, and C3H6 after sulfur poisoning and regeneration.

Automated summary

Diesel oxidation catalysts were studied for their oxidation activity, NO conversion stability, and sulfur poisoning/regeneration properties on different catalysts. The Pd-Pt/Al2O3 catalyst showed superior performance in CO, C3H8, and C3H6 oxidation, but faced challenges in complete regeneration due to stable sulfates.