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Abstract In this study, high yields of CO are reported from CO₂using the silica (SiO₂) supported perovskite oxide, La_0.75Sr_0.25FeO₃(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 CO₂chemisorption 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 CO₂conversion by RWGS‐CL. 

Metal oxynitrides demonstrate promising activity for photocatalytic solar water splitting and CO2 reduction under solar irradiance aided by noble metals. Precise control of cation ratios in the oxynitrides is a necessary challenge needed to overcome for achieving effective band gap tuning. Here we report density functional theory-based calculations on intricate structure-function relationships of Zn-Ga based oxynitrides and correlate results with the experimental parameters. Crucial material property descriptors such as elemental composition, intrinsic lattice strain, and vacancy defects were exploited during the synthesis to achieve stable oxynitride photocatalysts that demonstrated CO2 conversion to CO under simulated solar spectrum, without any noble metal impregnation. The highest CO production rate surpassed that of TiO2 under the same conditions. This work inspires future research on oxynitride materials towards tailored optical properties and sustainable photocatalytic activity enabling large scale applications.