The mixed conducting perovskite-type La0.8Sr0.2Co1-yMnyO3 +/- delta family has been synthesised by a combinatorial method. This system including the two end member materials (y = 0 and 1) have been studied using temperature programmed methods in order to relate structure and composition to oxygen exchange under a hydrogen atmosphere. Oxygen is removed in two steps: firstly, labile surface oxygen from 350 to 450 degrees C and then more strongly bound lattice oxygen. A relationship between the B-site manganese and cobalt content and ease of removal of lattice oxygen was demonstrated over the temperature range of 600-820 degrees C. Removal of labile surface oxygen was independent of the B-site composition but associated with A-site cations on the external surface of the crystallites. (c) 2012 Elsevier B.V. All rights reserved.