Process for adsorbing and desording oxides of nitrogen

Abstract

The invention concerns materials for adsorbing and desorbing oxides of nitrogen NO and NO2 present in exhaust gases, in particular from the internal combustion engines of automotive vehicles operating in a medium which is super-stoichiometric in oxidizing agents, which can desorb the oxides of nitrogen by elevating the temperature, with respect to an adsorption temperature, the structure of the materials being composed of phosphate tetrahedra and containing at least one element (A) from groups IVB, VB, VIB, VIIB, IVA, optionally at least one element (B) selected from the group formed by alkali elements IA, alkaline-earth elements IIA, rare earths IIIB and transition metals, and optionally at least one metal (C) selected from the group formed by the precious metals of the platinum family (group VIII). These materials are insensitive to the oxides of sulphur and carbon contained in the gas.

Dependencies are inferred from the claim text.