Temperature programmed oxygen evolution and electrical conductivity of a new series of fluorite compositions in La2-xPrxO3+y (1 <= x <= 2) system

Temperature programmed oxygen evolution (TPD) and electrical conductivity o f a new series of fluorite compositions in La2-xPrxO3+y (1 less than or equ al to x less than or equal to 2) system have been investigated. For x = 2, oxygen evolution occurs at three distinct steps, whereas for x less than or equal to 1.8, oxygen evolution occurs only in two steps and for x = 1 it b ecomes negligible. A decrease in the Pr-content in the fluorite composition s lowers the TPD peak intensity. The samples resorb oxygen on annealing at 650 degrees C in flowing oxygen and cooling the samples to room temperature revealing the reversible oxygen uptake and release feature. The electrical conductivity increases as a function of Pr-content in this series. For x l ess than or equal to 1.8, the temperature dependent conductivity shows brea ks at two temperature regions and the magnitude of the break is pronounced in Pr-rich compositions. Also, the activation energy decreases as the Pr-co ntent is increased in this series. The present results suggest that the flu orite compositions in this system might have potential as catalysts to stor e/transport/release oxygen reversibly.