Improved sulfur resistance of Pt-Sn/γ-Al2O3 catalysts for C3H8-NO-O2 reaction under lean conditions due to Pt-Sn surface interactions
✍ Scribed by Grisel Corro; J.L.G. Fierro; Ramón Montiel; Fortino Bañuelos
- Publisher
- Elsevier Science
- Year
- 2005
- Tongue
- English
- Weight
- 347 KB
- Volume
- 228
- Category
- Article
- ISSN
- 1381-1169
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✦ Synopsis
The selective catalytic reduction (SCR) of NO with C 3 H 8 was studied over unsulfated and pre-sulfated 1% Pt/␥-Al 2 O 3 , and 1% Pt-2% Sn/␥-Al 2 O 3 catalysts. Carbon residues deposited were evaluated on all samples, after 12 h of C 3 H 8 -NO-O 2 -SO 2 reaction. X-ray photoelectron spectra (XPS) were recorded over unsulfated and pre-sulfated fresh samples. Pre-sulfated 1% Pt-2% Sn/␥-Al 2 O 3 catalyst showed a high resistance to deactivation by sulfur during C 3 H 8 -NO-O 2 -SO 2 reactions. Results are explained on basis of the effect of tin addition to 1% Pt/␥-Al 2 O 3 that results in (i) lowering the sulfates generated over the surface of the catalyst during sulfation; and (ii) preventing Pt particles from sintering during sulfation process. We also investigated the effect of Sn addition to 1% Pt/␥-Al 2 O 3 catalyst, and the effect of pre-sulfation on 1% Pt/␥-Al 2 O 3 and 1% Pt-2% Sn/␥-Al 2 O 3 , on carbon depositions over the catalysts. Results showed a strong diminution of carbon depositions on sulfated 1% Pt-2% Sn/␥-Al 2 O 3 due to Pt-Sn surface interactions. The facts that tin addition to a Pt/␥-Al 2 O 3 catalyst, prevents Pt particles from sintering during high temperature sulfation and that sulfating a 1% Pt-2% Sn/␥-Al 2 O 3 catalyst prevents carbon residues deposition over the catalyst, suggest that this catalyst could resist high temperature reactions during automotive exhaust control without deactivation.