The interaction of soot with nitrates stored on a model PtBa/Al 2O 3 LNT catalyst sample is here investigated under realistic conditions, i.e. upon lean/rich cycling in the presence of water and CO 2. The presence of soot inhibits the NO x storage capacity of the catalyst during the lean phase at different temperatures, in the range 200-350°C, but does not affect significantly the regeneration process of the stored nitrates. Simultaneously with the NO x storage, soot is converted to CO 2 at temperatures above 300°C. Soot is oxidized by NO 2 formed by NO oxidation on Pt sites, but the participation of the stored nitrates in the soot oxidation is also likely, as pointed out by TPD/TPO experiments showing the occurrence of a surface reaction involving soot and the stored nitrates.
- Diesel particulate NO reduction
- DPNR catalysts
- NSR catalysts
- Simultaneous NO and soot removal
- Soot oxidation
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