Effects of Pt dispersion on electronic and oxide ionic conductivity in PrNiCuGaO

The effects of dispersing Pt particles in bulk Pr 1.90 Ni 0.71 Cu 0.21 Ga 0.05 O 4+ δ (PNCG) on the electrical conductivity and oxygen permeability of the material were studied. The different thermal expansion coefficients of PNCG and Pt generated a mechanical compressive strain in the PNCG. This may cause the electrical conductivity to decrease in samples containing Pt. In contrast, the oxide ion conductivity estimated from the oxygen permeability increased upon dispersion of Pt. These variations appear to be related to the electron hole and interstitial oxygen concentrations. Moreover, the present study suggests that the mechanical strain induces a chemical strain via the introduction of oxygen defects as well as changes in cation valences. Pt dispersion in Pr 2 NiO 4 based oxides formed compressed strain and electrical conductivity decreases, however, the oxide ion conductivity increases by the compressed strain due to the decreased hole and the increased interstitial oxygen concentration.