(532al) Pelletized SiO2-Supported La0.5Ba0.5FeO3 for Low-Temperature CO2 to CO Conversion By a Reverse Water-Gas Shift Chemical Looping Process

Reverse water-gas shift chemical looping is a thermochemical process to convert carbon dioxide to carbon monoxide at a moderate temperature with high selectivity. Perovskite oxides, such as La_0.5Ba_0.5FeO₃ (LBF), are proved materials for the lab-scale RWGS-CL process. To transition toward industrialization of the process, this study focused on formed perovskite-oxide/silica composite pellets with sufficiently high crushing strength, prepared by extrusion and tableting methods. X-ray diffraction (XRD) confirmed that the supported material is a combined structure of LBF and SiO₂ crystals. Temperature-programmed reduction (TPR) and oxidation (TPO) experiments revealed CO₂ is converted to CO at 550°C by LBF/SiO₂ pellets, higher than 500°C by LBF. Experiments carried out in a fixed bed microreactor are fitted to a kinetic model, and a residence time distribution corrected model based upon a modified logistic function fit to real system step response. DRIFTS-MS experiments confirmed that adsorbed CO₂ is dissociated to CO. High material stability is proven by long-term RWGL-CL experiments combined with XRD. The CO₂ to CO yields are calculated in these experiments as 2.21, 2.41, and 2.35 mmol/g_LBF of 10 mm tableting, 6 mm tableting, and extrusion pellets, respectively. All pellets showed stable redox properties in 50 cycles of semi-batch reactor experiments, indicating that LBF/SiO₂ pellets are candidate materials for further scale-up evaluation.