In situ TG-MS study of NOx and soot removal over LNT model catalysts

• The coupled TG–MS techniques were applied to study the activity of model and modified LNT catalysts.
• The K presence shifts the maximum exothermal process to lower temperature, improving the soot removal process.
• The apparent activation energy calculated follows the order: Pt-Ba > Pt-Ba-K > Pt-K for O2 and NOx assisted soot removal.

The application of coupled thermogravimetric techniques allowed obtaining interesting information regarding NSR thermodynamic and kinetic for Pt-Ba/γ-Al2O3, Pt-K/γ-Al2O3 and Pt-Ba-K/γ-Al2O3 catalysts. The materials have been tested for simultaneous NOx and soot removal according to standard TRM protocol and soot combustion runs. The catalysts presented high performance in the individualized reaction of NOx reduction, soot oxidation and the simultaneous NOx and PM removal. The apparent activation energy calculated follows the order: Pt-Ba > Pt-Ba-K > Pt-K for O2 and NOx assisted soot combustion, being strongly influenced by the alkali element incorporation that shifts the maximum exothermal process to low temperature, improving the soot removal process.

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