Combined Cu-Fe and Mn-Ni oxygen carriers were investigated as bed" materials for-chemical-looping combustion.,The aim was to identify material combinations which yield oxygen carriers with a high reactivity towards gaseous fuels, such as CO, H-2 and CH4, as well as sufficient mechanical durability. For this purpose, 18 different oxygen carriers were spray-dried and calcined at defined temperatures. Gas conversion as well as release of gaseous oxygen was-investigated in a batch fluidized bed reactor setup at temperatures between 850 and 1050 degrees C. For testing the mechanical durability; a jet-cup attrition rig was used. Moreover, properties like specific surface area, oxygen transfer capacity and crystalline phase composition were examined to physically and chemically characterize the oxygen carrier particles. For both the Cu-Fe and Mn-Ni-based materials, oxygen carriers could be produced which showed a high reactivity with gaseous fuels like CO or CH4 while having a sufficiently high mechanical strength. These properties make them interesting candidates for application in chemical-looping combustion. (C) 2016 Elsevier B.V. All rights reserved.