Gas component detecting element and detector

A method for producing a gas component detecting element for detectors which comprises a sintered body of particles of titanium dioxide which changes in its electrical resistance depending on relative atmosphere of combustible components in an exhaust gas, catalyst particles being supported on the surface of the particles of titanium dioxide, the method comprising the following steps:

• preparing of the titanium dioxide,
• calcining the particles of the titanium dioxide,
• subjecting the calcined particles from said calcining step to a treatment for a enlarging a specific surface area A.sub.1 of the calcined particles before subjected to grinding and specific surface area A.sub.2 of the particles after subjected to grinding satisfies the relation A.sub.1 A.sub.2 <1.0, and to thereby increase surface defects thereof,
• supporting catalyst particles on the surface of the particles subjected to the grinding treatment, and
• sintering the particles which support the catalyst particles.

A method for producing a gas component detecting element for detectors comprising an electrical insulating substrate and the gas component detecting element which comprises a sintered body of particles of titanium dioxide which changes in its electrical resistance depending on relative atmosphere of combustible components in an exhaust gas, catalyst particles being supported on the surface of the particles of titanium dioxide, the method comprising the following steps:

• preparing the particles of titanium dioxide,
• calcining the particles of titanium dioxide,
• subjecting the calcined particles to a grinding treatment so that ratio of specific surface area A.sub.1 of the calcined particles before subjected to grinding and specific surface area A.sub.2 of the particles after subjected to grinding satisfies the relation A.sub.1 /A.sub.2 <1.0,
• impregnating the particles of titanium dioxide subjected to the grinding treatment with a mixed solution of chloroplatinic acid and rhodium chloride,
• adding an organic binder to the particles of titanium dioxide impregnated with the mixed solution to obtain a paste,
• providing the pasty particles of titanium dioxide on a electrical insulating substrate in the form of a film at a given thickness, and
• sintering the particles of titanium dioxide provided on the substrate at 800.degree.-1300.degree. C.