Oxygen isotope exchange in La2NiO(4±δ)

Phys Chem Chem Phys. 2016 Apr 7;18(13):9102-11. doi: 10.1039/c5cp05984d.

Abstract

Oxygen surface exchange kinetics and diffusion have been studied by the isotope exchange method with gas phase equilibration using a static circulation experimental rig in the temperature range of 600-800 °C and oxygen pressure range of 0.13-2.5 kPa. A novel model which takes into account distributions of the dissociative adsorption and incorporation rates has been developed. The rates of the elementary stages have been calculated. The rate-determining stages for a La2NiO(4±δ) polycrystalline specimen have been discussed. The diffusion activation energies calculated using the gas phase equilibration method (1.4 eV) differ significantly from those calculated using isotope exchange depth profiling (0.5-0.8 eV), which was attributed to the influence of different oxygen diffusion pathways.

Publication types

  • Research Support, Non-U.S. Gov't