Soot oxidation in low-O₂ and O₂-free environments by lanthanum-based perovskites: structural changes and the effect of Ag doping

Abstract

The use of La-based, Cu (LCO), Mn (LMO) and Fe (LFO) perovskites doped with Ag were studied for potential application as cGPF soot oxidation catalysts. Special emphasis was placed on...

Tailoring the Composition of BaxBO3 (B = Fe, Mn) Mixed Oxides as CO or Soot Oxidation Catalysts in Simulated GDI Engine Exhaust Conditions

“…In the absence of oxygen, as expected [43,81,82], all catalysts show lower soot conversions due to the lower amount of oxygen available (which only comes from the samples). Under these conditions, the BF sample shows the lowest T 25% , as it evolves the highest amount of low and intermediate oxygen species (α-O 2 and α -O 2 ; see Figure 7a) able to oxidize the soot.…”

Soot Erased: Catalysts and Their Mechanistic Chemistry

“…To date, PGM-free compounds studied for soot oxidation [84] have been discussed based on their classification. Perovskite catalysts have gained significant attention in recent years due to their potential applications in various catalytic processes, including soot oxidation [85]. They are normally represented using the formula ABO 3 , wherein the A and B parts represent two cations of dissimilar dimensions, while O is an anion bridge that interacts with cations (Figure 6) [86,87].…”

Modified BaMnO3-Based Catalysts for Gasoline Particle Filters (GPF): A Preliminary Study

“…However, no effect of the amount of copper or the synthesis method was observed because all the BaMnO 3 catalysts removed over the 40% of the initial soot at the end of the test, showing a low CO 2 selectivity, which is the opposite trend observed in TG-MS conditions (Figure 7). This fact is a consequence of the different soot: catalyst ratio used (1:4 for GC and 1:8 for TG-MS) because, under inert atmosphere, oxygen is only supplied by the perovskite (β-O 2 ) [40,42,44,69,73]. Thus, once the perovskite is not able to supply oxygen, the passive oxidation of soot is performed, yielding CO as the main product, as is observed in Figure 9a.…”

“…It has been widely proved that soot oxidation can be catalyzed by O 2 , by NO and by a mixture of both NO-O 2 [27,[38][39][40]. Nevertheless, the composition of a GDI exhaust is poor in NO x , with the fuel cuts (i.e., when the engine pumps air from the intake to the exhaust [41,42]) being the only source of oxygen, and most of this is used by the threeway catalyst (TWC). Therefore, a good catalyst for this application should be active to adsorb oxygen during the fuel cuts mode and release it in regular operating conditions.…”

“…Currently, GDI engines present a high fuel economy and reduced CO 2 emission (compared to other gasoline engines), which positioned them as the most bought passenger car in 2017 [43]. However, due to the presence of a fuel-rich stage, leading to the incomplete combustion of the remaining fuel into the chamber, a large amount of small soot particles are formed that present a high health risk [42,43].…”