Patent ID: 6818582
Filing Date: 2004-11-16
Classification: B01D,B01J,F01N,Y02A,Y02T

Abstract:
An adsorbent catalyst for reducing amounts of nitrogen oxides, hydrocarbons and carbon monoxide contained in exhaust or combustion gases, wherein the catalyst adsorbs nitrogen oxides when the exhaust or combustion gases contain an excess of oxygen, and liberates and reduces the adsorbed nitrogen oxides when said gases contain oxygen in stoichiometric amounts or less, the adsorbent catalyst comprising a porous support material containing at least the following components:(i) a first catalytic metal comprising Pt; (ii) a first NOx adsorbent comprising at least one of the following metals: Ba and Sr; (iii) a second NOx adsorbent comprising at least one of the following metals: La and Y; and (iv) a redox NOx adsorbent comprising at least one of the following metals: Ce, Zr, Ti, Nb, Mn, Pr, Nd, Sm, Eu and Gd; wherein components (i)-(iv) are present in an amount effective to adsorb nitrogen oxides when the exhaust or combustion gases contain an excess of oxygen, and liberate and reduce the adsorbed nitrogen oxides when said gases contain oxygen in stoichiometric amounts or less.