Physicochemical properties of rare earth perovskite oxides used as gas sensor material

The change of the conductivity in the rare earth perovskite oxide took place after the chemisorption of flammable gases. The sensitivity for methanol was highest. From the conductivity change of these perovskite oxides after the injection of methanol, the energy needed to promote an electron from a conducting to a nonconducting state, E=E _c-E _t, could be derived from the equation=A ₀ exp (–E/kT). LnCoO₃ had the smallest E and H (metal-O), which is the binding energy of oxygen coordinating to the metal ions, but exhibited the highest activity for gas sensing. The gas sensing mechanism was also considered.