Use of CeO2-based oxides in the three-way catalysis

The infrared spectral performance of the N x O y species observed on oxide surfaces [N2O, NO−, NO, (NO)2, N2O3, NO+, NO2 − (different nitro and nitrito anions), NO2, N2O4, N2O5, NO2, and NO3 − (bridged, bidentate, and monodentate nitrates)] is considered. The spectra of related compounds (N2, H-, and C-containing nitrogen oxo species, C─N species, NH x species) are also briefly discussed. Some guidelines for spectral identification of N x O y adspecies are proposed and the transformation of the nitrogen oxo species on catalyst surfaces are regarded.

Identification of Neutral and Charged N x O y Surface Species by IR Spectroscopy

Molecular beam experiments on model catalysts

There are several problems related to the application of currently available NO x control technologies (i.e. three-way catalysts and the selective catalytic reduction of NO by NH 3 ) to lean burn diesel engines, and thus a very significant market potential exists for an improved technology in this area. As a result, the selective catalytic reduction of NO by hydrocarbons derived from on board fuel has received a lot of attention in the past five years. Different forms of base and noble metal exchanged zeolites, as well as supported noble metals appear to be the most active catalysts for this family of reactions. The available literature in this area is summarized in this review, with emphasis placed on the performance of different zeolite and supported noble metal catalysts, the effect of the various exhaust gas components and the mechanistic implications.

Selective catalytic reduction of nitric oxide by hydrocarbons

Cerium−zirconium mixed oxides (CexZr(1-x)O2), precalcined at 900 °C in dry air, were supplied by Rhodia Terres Rares as monophasic solid solutions. Introduction of some zirconium atoms in the ceria...

T.E. Hoost

Papers

An XRD and TEM Investigation of the Structure of Alumina-Supported Ceria–Zirconia

FTIR Spectroscopy of Nitric Oxide Adsorption on Pd/Al2O3: Evidence of Metal-Support Interaction