Surface modification of La0.8Sr0.2CrO3−δ–YSZ dual-phase membranes for syngas production

Abstract

Oxygen permeation fluxes were studied in Mixed Ionic and Electronic Conducting (MIEC) membranes based on composites of 40 vol% La_0.8Sr_0.2CrO₃ (LSCr) and 60 vol% yttria-stabilized zirconia (YSZ), using ambient air and flowing CO to establish a P(O₂) gradient. The ambipolar conductivity of the dense LSCr–YSZ composite was determined for membranes with dense layers that were 115 μm and 650 μm thick. Other parts of the investigation focused on how modifications to the surface on the CO side affected the fluxes. Using a porous LSCr–YSZ composite on the surface as the base case, oxygen fluxes were shown to increase dramatically upon addition of 5 wt% CeO₂ as a catalyst and an additional increase was observed with 1 wt% Pt. Changes in the structure of the porous composite LSCr–YSZ surface to improve connectivity of the YSZ phase also led to large increases in the oxygen fluxes.