(538b) Role of Ba in Low-Temperature Thermochemical Conversion of Carbon Dioxide with LaFeO3 Perovskite Oxides

To repropose CO₂ emission to value-added chemical products, reverse water-gas shift chemical looping (RWGS-CL) is proposed to convert CO₂ to CO by perovskite oxide materials at low-temperature. In this research, perovskite oxides of the form of La_1-xBa_xFeO₃ (x=0.25-0.75) are explored for enhancing CO yield while maintaining stability over multiple cycles. DFT was utilized to calculate the oxygen vacancy formation energies (E_vac) identifying E_vac of La_0.75Ba_0.25FeO₃ (3.3 eV) and La_0.5Ba_0.5FeO₃ (3.0 eV) are in the ideal range of 3.4 ± 0.5 eV. XRD confirmed cubic perovskite structure and XRF analysis established the precise composition. XPS revealed that the materials had Ba enrichment at the surface, compared to the overall bulk. Temperature-programmed reduction (TPR) and oxidation (TPO) experiments determined that CO₂ is converted to CO in the low-temperature range of 400 to 600 °C for all compositions, which is lower than the temperatures of many thermochemical CO₂ processes. Isothermal cycling between hydrogen and CO₂ at 600 °C indicated La_0.5Ba_0.5FeO₃ and La_0.4Ba_0.6FeO₃ were stable (verified by XRD and XPS) and produced CO at high yields of 200 and 500 μmol/g_LBF, respectively. Therefore, the multiple materials in this study enhance performance, indicating their suitability for industrial-scale adaptation upon energy integration as a possible strategy for renewable energy storage in chemical form.