Hy. Huang et al., A highly sulfur resistant Pt-Rh/TiO2/Al2O3 storage catalyst for NOx reduction under lean-rich cycles, APP CATAL B, 33(2), 2001, pp. 127-136
Citations number
31
Categorie Soggetti
Physical Chemistry/Chemical Physics","Environmental Engineering & Energy
Pt-Rh/TiO2/Al2O3 was investigated as a NOx storage-reduction catalyst using
lean-rich cycles. It was found to be highly effective for NOx reduction an
d highly resistant to SO2 and H2O. In the presence of 100 ppm SO2 and 2.3%
H2O, approximately 90% of NOx conversion was obtained at 250 degreesC and a
GHSV of 30,000 h(-1) after 5 h lean-rich cyclic runs. A model NOx trap cat
alyst, Pt-Rh/BaO/Al2O3, was used for comparison. In the absence Of SO2 and
H2O, nearly complete removal of NOx was achieved. NOx conversion dropped to
only 30% after SO2/H2O were introduced into the reactant gases at 300 degr
eesC. With Pt-Rh/TiO2/Al2O3, over 70% NO conversion was still obtained at 4
00 degreesC. Although, the BaO containing catalyst has much higher capacity
for NOx than that containing TiO2, it is much more susceptible to SOx pois
oning. In situ Fr-IR spectra of the titania catalyst showed that nitrate sp
ecies was the final adspecies (i.e. at the end of the lean phase) on the st
orage catalyst and its intensity was only slightly weakened in the presence
Of SO2 and H2O. (C) 2001 Elsevier Science B.V. All rights reserved.