Iron‐Doped BaMnO3 for Hybrid Water Splitting and Syngas Generation

• Published in: ChemSusChem 2017-09, Vol.10 (17), p.3402-3408
• Main Authors: Haribal, Vasudev Pralhad, He, Feng, Mishra, Amit, Li, Fanxing
• Format: Article
• Language: English
• Subjects: Carbon dioxide; Catalysts; chemical looping; Conversion; Fuel production; Hydrogen; Hydrogen production; Methane; Oxidation; perovskite; State of the art; syngas; Synthetic fuels; Transition metal oxides; Water splitting
• ISSN: 1864-5631; 1864-564X
• DOI: 10.1002/cssc.201700699

A rationalized strategy to optimize transition‐metal‐oxide‐based redox catalysts for water splitting and syngas generation through a hybrid solar‐redox process is proposed and validated. Monometallic transition metal oxides do not possess desirable properties for water splitting; however, density functional theory calculations indicate that the redox properties of perovskite‐structured BaMnxFe1−xO3−δ can be varied by changing the B‐site cation compositions. Specifically, BaMn0.5Fe0.5O3−δ is projected to be suitable for the hybrid solar‐redox process. Experimental studies confirm such predictions, demonstrating 90 % steam‐to‐hydrogen conversion in water splitting and over 90 % syngas yield in the methane partial‐oxidation step after repeated redox cycles. Compared to state‐of‐the‐art solar‐thermal water‐splitting catalysts, the rationally designed redox catalyst reported is capable of splitting water at a significantly lower temperature and with ten‐fold increase in steam‐to‐hydrogen conversion. Process simulations indicate the potential to operate the hybrid solar‐redox process at a higher efficiency than state‐of‐the‐art hydrogen and liquid‐fuel production processes with 70 % lower CO2 emissions for hydrogen production Perovskite power: BaMn0.5Fe0.5O3−δ demonstrates over 90 % water‐splitting conversion and over 90 % syngas‐yield using a hybrid solar‐redox process. Computational modelling, fluidized‐bed experiments, and in situ XRD analysis indicate that perovskite BaMn0.5Fe0.5O3−δ is ideal for the proposed redox reactions. Process simulations indicate a 70 % reduction in CO2 emissions for hydrogen production compared to the current state‐of‐the‐art processes.