Influence of reducing agent (CO, H2, and C2H4) and of H2O on NOx reduction on a Pt-Ba/γ-Al2O3 catalyst

Reaction Pathways in the Reduction of NO x Species by CO over Pt–Ba/Al2O3: Lean NO x Trap Catalytic Systems

“…This can be explained on the basis of self-poisoning effects of CO on the Pt active sites. As a matter of fact IR data showed the formation of bands attributed to carbonyls species on Pt sites (2070-2056-2035 cm -1 ), which poisoned the active Pt sites [16,21]. It is hence speculated that both at 300 and 350°C further N 2 formation is inhibited by CO-poisoning on Pt.…”

Effects of temperature and rich-phase composition on the performance of a commercial NOx-Storage-Reduction material

“…A description of the NSR technique 5 and a review of the activity of many materials have been reported elsewhere [3]. The 6 understanding of NSR technology has been hampered by the fact that various (usually non-7 realistic) reaction conditions were often used and a very large number of model materials with 8 varying formulations were investigated [4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22]. 9 Several studies have been devoted to commercial NSR materials [23,24,25,26] and in 10 situ FTIR studies [27,28,29,30], but rarely the combination of the two has been reported.…”

“…0.1 ± 0.05 wt.%). As far as oxides were concerned, the main 6 constituents were the following, in order of decreasing concentration: Al (ca. 25 ± 5 wt.%), 7 Ce (ca.…”

“…In such cases, all carbon-containing species were removed from the 4 reduction feed after 30 min, allowing the sample to be activated only under H 2 (using the "C-5 free" feed) for another 30 min. A computer-controlled automated 6-way valve (Swagelok) 6 was used to switch either the lean or rich feed to the reaction cell in addition to the base feed. 7 The NSR material was typically stabilized over five full cycles before five other cycles were 8 collected to calculate an averaged NSR activity.…”

Effects of temperature and reductant type on the process of NOx storage reduction over Pt/Ba/CeO2 catalysts

“…Two small peaks centered at 2175 and 2121 cm −1 were related to gaseous CO [42] ranges, and reached a maximum at the end of the reduction. The Pt-CO species have been commonly found on the Pt/Ba/Al 2 O 3 catalyst when using CO as a reducing agent, and have a strong influence on NSR performance [30,38,43]. Specifically, in a typical NSR process, Pt plays an important role in NO oxidation and reduction.…”