title: Mono- and bimetallic Rh and Pt NSR-catalysts prepared by controlled deposition of noble metals on support or storage component.
abstract: Mono- and bimetallic Rh and Pt based NOxstorage-reduction (NSR) catalysts, where the noble metals were deposited on the Al2O3support or BaCO3storage component, have been prepared using a twin flame spray pyrolysis setup. The catalysts were characterized by nitrogen adsorption, CO chemisorption combined with diffuse reflectance infrared Fourier transform spectroscopy, X-ray diffraction, and scanning transmission electron microscopy combined with energy dispersive X-ray spectroscopy. The NSR performance of the catalysts was investigated by fuel lean/rich cycling in the absence and presence of SO2(25 ppm) as well as after H2desulfation at 750 °C. The performance increased when Rh was located on BaCO3enabling good catalyst regeneration during the fuel rich phase. Best performance was observed for bimetallic catalysts where the noble metals were separated, with Pt on Al2O3and Rh on BaCO3. The Rh-containing catalysts generally showed much higher tolerance to SO2during fuel rich conditions and lost only little activity during thermal aging at 750 °C.
authors.affiliation: Particle Technology Laboratory, Department of Mechanical and Process Engineering, ETH Zurich, Sonneggstrasse 3, CH-8092 Zurich, Switzerland ; Department of Chemistry and Applied Biosciences, ETH Zurich, Hönggerberg, HCI, CH-8093 Zurich, Switzerland.
authors.forename: Robert
authors.initials: R
authors.lastname: Büchel
authors.forename: Sotiris E
authors.initials: SE
authors.lastname: Pratsinis
authors.forename: Alfons
authors.initials: A
authors.lastname: Baiker
keywords: Flame spray pyrolysis; NOx storage-reduction (NSR); alumina; barium carbonate; fast NOx storage; lean NOx trap; mono- and bimetallic catalyst; platinum; rhodium; selective deposition; sulfur poisoning