In chemical looping combustion (CLC), a necessary oxygen polishing step exerted an additional cost to the technology due to an extra demand of pure O-2. However, the additional cost can be lowered if the oxygen carriers can produce gaseous oxygen, i.e. has a chemical looping with oxygen uncoupling (CLOU) property. A CLC+ CLOU scheme is proposed in the study. Production of gaseous O-2 using a manganese ore and the Cu-modified manganese ore as oxygen carriers were investigated. The reaction kinetics of the two oxygen carriers were studied by thermogravimetric analysis (TGA). Multiple O-2 uptake and release cycles were carried out to demonstrate the good stability of the oxygen carriers. Continuous tests with both oxygen carriers were carried out in a dual fluidized bed. Results showed that both oxygen carriers could be fluidized well in the continuous run and a stream of O-2 could be obtained stably. The Cu-modified manganese ore showed higher oxidation rate and oxygen transport capacity than the original manganese ore. Both materials have advantage economically and could be promising for O-2 production in the CLC + CLOU scheme.