Method for fabricating high-activity electrodes for exhaust gas sensors

A method for fabricating a high-activity cermet electrode which is applied on an exhaust gas sensor including an oxygen ion conducting solid electrolyte, which is comprised of a cermet material comprising at least one catalytically active material and at least one oxygen ion conducting ceramic material, which is bonded to the solid electrolyte of the exhaust sensor by co-sintering the cermet electrode and the solid electrolyte at a temperature ranging from 1300.degree. to 1600.degree. C. to provide a porous cermet electrode, and which contains at least one further catalytically active material which is embedded in the pores of the porous cermet electrode after co-sintering, the method comprising:

• a. bonding together an unsintered solid electrolyte which conducts oxygen ions and a cermet electrode by co-sintering at from 1300.degree. to 1600.degree. C. to provide a porous cermet electrode;
• b. subsequently introducing at least one further catalytically active material into pores of the porous cermet electrode by impregnation thereof with a solution containing a solvent and at least one compound selected from the group consisting of inorganic compounds of platinum group metals and organic compounds of platinum group metals;
• and
• c. tempering the cermet electrode at a temperature ranging from 300.degree. to 900.degree. C. after evaporating the solvent to thereby decompose the at least one compound and provide a metallic residue.