Solid electrolyte gas sensor comprising a catalytic metal containing protecting layer and method for manufacturing the same

摘要

A gas sensor comprising a gas sensor element which includes: a reference electrode; a solid electrolyte layer having oxygen ion conductivity; a detection electrode; and an electrode-protecting layer covering the detection electrode. The electrode-protecting layer is a porous body carrying catalytic metal, and includes: a detection electrode side portion having a catalytic metal loading ratio of more than 0 % by weight and not more than 0.005 % by weight; and a surface side portion provided closer to the outer surface of the electrode-protecting layer than the detection electrode side portion, the surface side portion having a catalytic metal loading ratio of 0.01 % by weight or more. This concentration gradient of the catalytic metal in the protective layer prevents the peeling off the protective coating from the electrode.