The study of CO2 splitting kinetics on LSM perovskite oxides in the solar-driven two-step thermochemical cycle

La0.6Sr0.4MnO3 (LSM) has seen enormous interest since they were proposed for the two-step thermochemical cycle (TSTC). However, its oxidation kinetics is notably deficient, and few studies have been documented. In this work, the reactivity activity relaxation (RAR) and electrical conductivity relaxation (ECR) methods are used to investigate the reaction kinetics of CO2 splitting by LSM oxidation. The results of RAR test show that the SestakBerggren model is the most precise depiction of the reaction mechanism, and the apparent kinetic parameters are obtained. In addition, the chemical bulk diffusion coefficient and the oxygen surface exchange coefficient of the reactions are obtained using the ECR method. It's found that the surface reaction process is the rate-limiting step of the whole oxidation reaction process. In conclusion, this study examines in detail the kinetic properties of LSM oxidation reaction and provides a reference for its application in TSTC.