High performances of Pt-K/Al2O3 versus Pt-Ba/Al2O3 LNT catalysts in the simultaneous removal of NO x and soot

Abstract

The potentiality of a Pt-K/Al 2 O 3 catalyst in the simultaneous removal of particulate matter (soot) and NO x is investigated in this work by means of Temperature Programmed Oxidation (TPO) experiments and Transient Response Method (TRM), and compared with Pt-Ba/Al 2 O 3 . The results point out the higher performances of K-based sample in the soot combustion as compared to the Ba-based catalyst, and similar behaviour in the NO x -storage.

Simultaneous Removal of NO x and Soot Over Pt–Ba/Al2O3 and Pt–K/Al2O3 DPNR Catalysts

“…The features of the reduction of the stored NO x , with NH 3 formation following that of N 2 , were already discussed elsewhere [3,4]. Along with N 2 and NH 3 production, non-negligible amounts of NO and CO 2 are also detected at the reactor outlet.…”

“…The Pt-Ba/Al 2 O 3 (1/20/100 w/w) and Pt-K/Al 2 O 3 (1/5.4/ 100 w/w) catalysts used in this study were prepared by incipient wetness impregnation of an alumina support with aqueous solutions of dinitro-diammine platinum, Ba or K acetate [4]. Printex-U (Degussa) was used as model soot, whose properties were well addressed, e.g., in [6,7].…”

“…Experiments were performed at different temperatures, in the range 250-350°C. Further details on the experimental setup and procedures are reported elsewhere [3,4].…”

“…The capability of model Pt-Ba/Al 2 O 3 and Pt-K/Al 2 O 3 DPNR catalysts to accomplish the simultaneous removal of PM and NO x has been documented by our group [3,4]. It has been shown that soot oxidation occurs during the lean phase only, while NO is being oxidized to NO 2 and nitrites/ nitrates are being stored on the catalyst surface.…”

Strong Enhancement of deSoot Activity of Transition Metal Oxides by Alkali Doping: Additive Effects of Potassium and Nitric Oxide

“…A systematic shift of the temperature window of soot combustion on potassium-promoted spinels in the presence of NO was also reported [23]. It was found that potassium-containing catalysts can be used for the simultaneous removal of NO x and soot [24][25][26], so similar catalytic systems were also investigated in bench-scale experiments [26][27][28].…”