Production of O-2-CO23 mixed gases for the oxyfuel combustion using a Co-based oxygen carrier packed in a fixed bed reactor was investigated. The reaction kinetics of CoO with O-2 and the decomposition kinetics of Co3O4 in CO2 atmosphere at different temperatures were studied using thermogravimetric analysis (TGA). Both desorption and sorption processes exhibit a high reaction rate. Multiple sorption and desorption cycles indicated that Co-based oxygen carrier has high reactivity and cyclic stability. The results of X-ray diffraction indicated that Co-based oxygen carrier does not react with CO2 during the desorption stage, and this is especially important for oxyfuel combustion. The high temperature sorption process for production of O-2-CO2 gas mixtures in a fixed bed reactor packed with Co-based oxygen carrier particles through air separation with carbon dioxide as the purge gas is investigated. Oxygen is absorbed, and heat is stored by the Co-based oxygen carrier particles with air being fed. An O-2-CO2 stream can be obtained when the fixed bed is regenerated with carbon dioxide as the desorption gas. O-2 fraction in the O-2-CO2 gas mixtures can be controlled by adjusting the flow rate of CO2 regeneration gas. This Co-based oxygen carrier offers potential for further study in the O-2-CO2 production for the oxyfuel coal combustion process.