Sol-gel processed silica-alumina materials for diesel engine emission reduction catalysts

C. K. Narula, M. Rokosz, L. F. Allard, R. J. Kudla, M. S. Chattha

Research output: Contribution to journalArticlepeer-review

12 Scopus citations

Abstract

The incorporation of >30% silica in alumina prior to platinum impregnation improves the NOx conversion efficiency in the 200-300 °C range from 45 to 57% and reduces light-off temperature. Further increase in the amount of silica to 50% is detrimental to NOx conversion efficiency. The 1H and 29Si NMR of the materials suggest that this trend is probably related to the surface acidity. The analyses of these materials by X-ray powder diffraction and electron microscopy do not reveal significant differences. Additional NOx conversion in the 350-450 °C range with a maximum of 30% at 400 °C can be achieved if a rhodium-impregnated 30% silica-alumina. Rh-30% SiO2-Al2O3, is placed upstream of Pt-30% SiO2-Al2O3. It is important to note that mixing Pt-30% SiO2-Al2O3 with Rh-30% SiO2-Al2O3 does nor enhance conversion efficiency or effective temperature range.

Original languageEnglish
Pages (from-to)3818-3822
Number of pages5
JournalLangmuir
Volume16
Issue number8
DOIs
StatePublished - Apr 18 2000
Externally publishedYes

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