Solid-state mixed-potential sensor employing tin-doped indium oxide sensing electrode and scandium oxide-stabilised zirconia electrolyte

The sensing properties of the planar mixed-potential CO sensor coupling scandia-stabilized zirconia (ScsZ) as electrolyte and tin-doped indium oxide (ITO) as sensing electrode to different CO concentrations from ∼100 ppm to ∼500 ppm have been investigated. The monodispersed ITO particles with spherical shape have been obtained by hydrothermally treating the mixture of the coprecipitated gels with urea as an additive. Directly using urea as the mineralizer, the two coexisting morphologies such as rod-like and spherical shapes have been obtained. The sensor coupling spherical 5 at.% tin-doped indium oxide (5ITO) electrode shows better sensitivity than the sensors coupling both spherical 8 at.% tin-doped indium oxide (S8ITO) and 8 at.% tin-doped indium oxide (RS8ITO) containing rod-like particles. The sensor coupling spherical 5 at.% tin-doped indium oxide (5ITO) electrode also exhibits highly reproducible and stable signals to different CO concentrations.