(US5037525-A)      Oxygen ion-conducting solid electrolyte device has a solid electrolyte (I) which is impervious to gas and is selected from zirconia, hafnia, thoria and ceria, doped or alloyed with one or more oxides selected from calcia, magnesia, yttria, scandia and rare earth oxides. (I) carries at least one electrode comprising a mixt. of a minor amt. of a noble metal selected from platinum, silver, gold, palladium, iridium and rhodium, and mixts. and alloys of any two or more of these metals, and a major amt. of a semiconducting metal oxide with either electronic n-type or hole p-type conductivity, selected from the semiconducting oxides or complex oxides of one or more of the transition metals having atomic numbers 24-30, metals having atomic numbers 49-50 and the lanthanides having atomic numbers 57-71. The noble metal is present in an amt. ranging from an amt. effective to lower the time constant and the electrode resistance of the electrode w.r.t. either the noble metal alone, or the semiconducting metal oxide alone, up to an amt. of 40% by wt.    ADVANTAGE -   New device generates ideal (i.e. Nernstian) emfs under oxygen-excess gaseous condition at temps. substantially below those at which conventional noble metal or metal oxide electrodes begin to show non-ideal behaviour. @(32pp)@    (JP2541530-B2)      Composite electrode material for use in solid electrolyte devices comprises a mixt. of a noble metal and a p- or n-type semiconducting metal oxide. Pref. noble metals are Pt, Ag, Au, Pd, Ir and Rh and alloys or mixts. of these; pref. semiconducting oxides are oxides of transition metals of at. nos. 21-30, 39-48 and 72-80; lanthanides 57-71; and actinides 89-96.    Oxide component is a cpd. or solid soln. of one or more binary oxides or simple oxide(s).    USE/ADVANTAGE -   In O2 sensors, O2 pumps, fuel cells, steam electrolysis cells and electrochemical reactors. Electrodes have superior properties to those of the metals or oxides alone, e.g. O2 sensors may operate at emps. as low as 300 deg. C.