Soot oxidation on a catalytic NOx trap: Beneficial effect of the Ba-K interaction on the sulfated Ba,K/CeO2 catalyst

V.G. MILT; M.A. PERALTA; M.A. ULLA; E.E. MIRÓ

CATALYSIS COMMUNICATIONS

Elsevier

Año: 2007 vol. 8 p. 765 - 769

1566-7367

Abstract The Ba,K/CeO2 catalyst is active both for NOx trapping and soot combustion. In this work we report a Ba–K interaction that prevents K sulfation when NOx is present, thus preserving the activity of K towards soot combustion during the working period of the trap. This e.ect is originated in the K2SO4(s) + Ba(NO3)2(s) !2KNO3(s) + BaSO4(s) reaction, which is thermodynamically favored. In the absence of NOx, the soot combustion reaction is strongly depressed by SO2 whereas when NOx is present both the sulfated and the non-sulfated catalysts present similar TPO patterns.2 catalyst is active both for NOx trapping and soot combustion. In this work we report a Ba–K interaction that prevents K sulfation when NOx is present, thus preserving the activity of K towards soot combustion during the working period of the trap. This e.ect is originated in the K2SO4(s) + Ba(NO3)2(s) !2KNO3(s) + BaSO4(s) reaction, which is thermodynamically favored. In the absence of NOx, the soot combustion reaction is strongly depressed by SO2 whereas when NOx is present both the sulfated and the non-sulfated catalysts present similar TPO patterns.x is present, thus preserving the activity of K towards soot combustion during the working period of the trap. This e.ect is originated in the K2SO4(s) + Ba(NO3)2(s) !2KNO3(s) + BaSO4(s) reaction, which is thermodynamically favored. In the absence of NOx, the soot combustion reaction is strongly depressed by SO2 whereas when NOx is present both the sulfated and the non-sulfated catalysts present similar TPO patterns.2SO4(s) + Ba(NO3)2(s) !2KNO3(s) + BaSO4(s) reaction, which is thermodynamically favored. In the absence of NOx, the soot combustion reaction is strongly depressed by SO2 whereas when NOx is present both the sulfated and the non-sulfated catalysts present similar TPO patterns.x, the soot combustion reaction is strongly depressed by SO2 whereas when NOx is present both the sulfated and the non-sulfated catalysts present similar TPO patterns. 2006 Elsevier B.V. All rights reserved.2006 Elsevier B.V. All rights reserved. Keywords: Ba,K/CeO2 catalysts; Ba–K interaction; NOx traps; Diesel soot combustion; Sulfur poisoningBa,K/CeO2 catalysts; Ba–K interaction; NOx traps; Diesel soot combustion; Sulfur poisoning