On the Steady-State Oxygen Permeation Through La[sub 2]NiO[sub 4+δ] Membranes

Abstract

The steady-state oxygen permeation through polycrystalline La2 Ni O4+?, synthesized by a citric acid-based technique and sintered at 1350?C, has been measured as a function of oxygen gradient, temperature (850-1000?C), and membrane thickness (0.3-2.5 mm). In agreement with earlier reports, the La2 Ni O4+? membranes show high permeation rates, comparable to those found for the perovskite-related La1-x Srx Co1-y Fey O3-? materials. The self-diffusion coefficient and the surface exchange coefficient of oxygen are extracted from the data through transport modeling using averaged bulk transport parameters and through numerical analysis based on a one-dimensional finite-element method. The self-diffusion coefficient and surface exchange coefficients show Arrhenius-type behavior with activation energies 40?20 and 110?60 kJmol, respectively, and agree qualitatively with literature data obtained by O216 O218 exchange/secondary ion mass spectroscopy analysis at lower temperatures. ? 2005 The Electrochemical Society. All rights reserved.