In the previous work, YBaCo 4 O 7 + δ and Y 0.2 Ti 0.05 Dy 0.75 BaCo 4 O 7 + δ monolithic oxygen carriers worked at low temperature, were reported with good reactivity in oxygen absorption and desorption. Oxygen carriers reacted at low temperature can save amount of energy for the chemical looping air separation process. The objective of this work is to explore the detailed effect of new foreign ion K + on reaction process of oxygen releasing and the reduction kinetics for YBaCo 4 O 7 + δ and Y 0.2 Ti 0.05 Dy 0.75 BaCo 4 O 7 + δ monolithic oxygen carriers in fixed-bed reactor. The results showed that introducing K + can improve the reaction rate of oxygen releasing. The process of oxygen releasing can be described by A model with different model exponentials of 2, 3, and 4. Adding K + promotes reaction of oxygen releasing. The apparent activation energies and pre-exponential factor of oxygen releasing process range from 23.11 to 29.72 kJ/mol and 12.46 to 29.73 min À1 , respectively. The kinetic model of oxygen releasing process of monolithic oxygen carriers is established based on obtained kinetics parameters. The got kinetics parameters could be used for designing of a chemical looping air separation reactor.