Mesoporous Silica Supported Perovskite Oxides for Low Temperature Thermochemical CO<sub>2</sub> Conversion
Jeremy C. Brower, Bryan J. Hare, Venkat R. Bhethanabotla, John N. Kuhn
Abstract
Abstract In this study, high yields of CO are reported from CO 2 using the silica (SiO 2 ) supported perovskite oxide, La 0.75 Sr 0.25 FeO 3 (LSF), composites in the reverse water gas shift chemical looping (RWGS‐CL) process. XRD patterns of materials formed upon adding SBA‐15 to the perovskite sol‐gel precursor solution indicated successful formation of an orthorhombic perovskite oxide structure in the composites. The total surface area increased by ∼300 % with the addition of 50 % LSF to SBA‐15 by mass and surface accessibility of perovskite oxide crystallites was verified by CO 2 chemisorption and XPS measurements. Composite materials achieved up to a factor of 10 increases in CO yields (∼3.5 vs 0.35 mmol CO/g LSF ) compared to pure LSF through six consecutive RWGS‐CL cycles at 700 °C. Following these RWGS‐CL cycles, XRD Scherrer analyses showed that the perovskite oxide in the composite material decreased in crystallite size. This approach to synthesis of supported perovskite oxides is expected to be valuable for large‐scale CO 2 conversion by RWGS‐CL.