Abstract: The invention concerns materials for eliminating 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 oxidising agents, which can adsorb oxides of nitrogen then desorb the oxides of nitrogen by elevating the temperature with respect to the adsorption temperature or by passage of a rich mixture, said materials comprising mixed oxides the metals of which are in octahedral coordination, with the octahedra connecting together so that the structure generates lamellae. Said materials adsorb oxides of nitrogen by insertion and do not become poisoned in contact with oxides of sulphur and carbon contained in the gases. In the presence of a group VIII metal, said materials are capable of eliminating oxides of nitrogen adsorbed by reduction during the passage of a rich mixture.

Abstract: The invention concerns materials for eliminating oxides of nitrogen NO and NO2 present in exhaust gases, in particular from the internal combustion engines of automotive vehicles operating in a medium that is super-stoichiometric in oxidizing agents, which can adsorb oxides of nitrogen then desorb the oxides of nitrogen by elevating the temperature with respect to the adsorption temperature or by passage of a rich mixture, the materials comprising mixed oxides the metals of which are in octahedral co-ordination, with the octahedra connecting together so that the structure generates micropores in the form of channels. The channel width of the materials is such that the sides are composed of 2 and/or 3 octahedra. These materials adsorb oxides of nitrogen by insertion and do not become poisoned in contact with oxides of sulfur and carbon contained in the gases.

Abstract: The invention concerns materials for eliminating oxides of nitrogen NO and NO2 present in exhaust gases, in particular from the internal combustion engines of automotive vehicles operating in a medium that is super-stoichiometric in oxidizing agents, which can adsorb oxides of nitrogen then desorb the oxides of nitrogen by elevating the temperature with respect to the adsorption temperature or by passage of a rich mixture, the materials comprising mixed oxides the metals of which are in octahedral co-ordination, with the octahedral connecting together so that the structure generates micropores in the form of channels. The channel width of the materials is such that the sides are composed of 2 and/or 3 octahedra. These materials adsorb oxides of nitrogen by insertion and do not become poisoned in contact with oxides of sulfur and carbon contained in the gases.

Abstract: The invention concerns materials for eliminating 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 oxidising agents, which can adsorb oxides of nitrogen then desorb the oxides of nitrogen by elevating the temperature with respect to the adsorption temperature or by passage of rich mixture, said materials comprising mixed oxides the metals of which are in octahedral coordination, with the octahedra connecting together so that the structure generates micropores in the form of channels. These materials adsorb oxides of nitrogen by insertion and do not become poisoned in contact with oxides of sulphur and carbon contained in the gases. In the presence of a group VIII metal, these materials are capable of eliminating oxides of nitrogen absorded by reduction during passage of a rich mixture.

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.