A dense La0.7Sr0.3Ga0.3Fe0.7O3-delta membrane tube was treated with hydrogen by exposing its tube side to a H-2 stream and the shell side to the ambient air at 950 degrees C. A porous layer of thickness similar to 500 mu m was formed on the membrane surface (tube side) after 16 h treatment. The oxygen permeation measurement was performed by sweeping the tube side of the membrane with helium to carry away the permeated oxygen. The H-2-treated membrane exhibited a large increase in oxygen permeation flux (by a factor of 4.5 at 950 degrees C and 10.5 at 800 degrees C) and a significant reduction in the apparent activation energy, which is attributed to the increased porosity on the tube-side surface. It is suggested that the H-2 treatment altered the rate-limiting step from the surface oxygen exchange to the transport of oxygen in the bulk of the membrane. The H-2 treatment also led to an enhanced depletion of Ga from the membrane surface, which could affect the applicability of the membrane. (c) 2008 Elsevier B.V. All rights reserved.