Abstract: The invention relates to a structure for the purification of a contaminated gas, for example the exhaust gas from a diesel or petrol engine, the structure incorporating an electrochemical system for treating said gas, composed of an NOx reduction catalyst A, a hydrocarbon oxidation catalyst B, an electron-conducting compound C and an ion-conducting compound D, said structure being characterized in that it is made of or covered with at least one porous, inorganic, electron-conducting and/or ion-conducting material in such a way that the catalysts A and B are disposed in the porosity of the inorganic material and that the ion-conducting, electron-conducting or ion-conducting and electron-conducting inorganic material makes up, respectively, the element C, the element D, or the sum of the elements C and D of said electrochemical system.

Abstract: A method is provided for backwashing, by heating, a particulate filter to be purified of exhaust gases (G) of an internal combustion engine (M), in particular an internal combustion engine equipping a motor vehicle (V). The method includes controlling the start-up of a device for heating (1) the filter (F) when the engine (M) delivers an engine torque at a predetermined low threshold (Cbas).

Abstract: A process for the combustion treatment of carbonaceous particles collected on a filter situated in an exhausted circuit of an internal combustion engine is disclosed. The combustion of the particles is brought about by contacting them with a gas mixture including at least nitrogen dioxide generated within the exhaust circuit of the engine, the particles having been seeded prior to their combustion with at least one catalyst of their oxidation.

Abstract: In a method of manufacturing parts or powders made of a compound of silicon or of a metal by exothermally reacting parts or powders of silicon or a metal in the solid state with a gas, wherein the differential flow rate or the pressure variation of the reactive gas in contact with the part or the powder is sensed, and the reaction is performed at increasing temperatures as a function of the said differential flow rate or pressure of the reactive gas:the improvement wherein a maximum differential flow rate or a maximum speed of pressure drop of the reactive gas is predetermined as a function of the chemical nature of the parts or powders, and optionally as a function of the density and the size of the parts, and the rise in temperature is suspended when the differential flow rate or the speed of pressure drop of the reactive gas reaches the predetermined maximum value, beyond which the reaction would run away and prevent complete transformation of the parts or the powders being obtained.