Mono- and bimetallic Rh and Pt NSR-catalysts prepared by controlled deposition of noble metals on support or storage component

Mono- and bimetallic Rh and Pt based NOx storage-reduction (NSR) catalysts, where the noble metals were deposited on the Al2O3 support or BaCO3 storage 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 H2 desulfation at 750 °C. The performance increased when Rh was located on BaCO3 enabling good catalyst regeneration during the fuel rich phase. Best performance was observed for bimetallic catalysts where the noble metals were separated, with Pt on Al2O3 and Rh on BaCO3. The Rh-containing catalysts generally showed much higher tolerance to SO2 during fuel rich conditions and lost only little activity during thermal aging at 750 °C.

. Mono- and bimetallic Rh and Pt based NOx storage-reduction (NSR) catalysts with spatially controlled noble metal deposition were prepared using a twin flame spray pyrolysis setup. All catalysts performed well in the absence of SO2, while in the presence of SO2 Rh was essential.Figure optionsDownload as PowerPoint slideHighlights
► Mono- and bimetallic Rh and Pt based NSR catalysts were prepared by flame spray pyrolysis.
► Noble metals were selectively deposited on support (Al2O3) and storage component (BaCO3).
► The location of nobe metal deposition had a significant influence on the NSR performance.
► Rh containing catalysts showed superior NSR efficiency in the presence of SO2.
► Combinations of Rh and Pt enhanced the NSR performance of the catalysts.