Purification structure incorporating a biased electrochemical catalyst system

A device for purification of a polluted gas, comprising:

• a honeycomb structure comprising at least one porous electron-conductive material forming walls of said structure and an electrochemical system for treating said gas, comprising:
• a layer of an electronically insulating and ionically conductive material D,
• a reduction catalyst A for reducing the polluting species of the NOx type, in contact with the electronically insulating and ionically conductive material D which forms all or part of an electrode W or which is electrically connected to an electrode W and an oxidation catalyst B for oxidizing polluting species selected from the group consisting of soot, hydrocarbons, CO, H2, and mixtures thereof, in contact with the electronically insulating and ionically conductive material D which forms all or part of a counterelectrode CE or which is electrically connected to a counterelectrode CE,
• wherein the oxidation catalyst B contacts the electron-conductive material forming the walls of the honeycomb structure, wherein said layer of electronically insulating and ionically conductive material D is between the reduction catalyst A and the oxidation catalyst B so as to electronically isolate each catalyst from the other, and
• wherein the honeycomb structure is capable of simultaneously reducing polluting species of the NOx type and oxidizing polluting species selected from the group consisting of soot, hydrocarbons, CO, H2, and mixtures thereof.