Iron‐Doped BaMnO 3 for Hybrid Water Splitting and Syngas Generation

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 BaMn x Fe 1− x O 3− δ can be varied by changing the B‐site cation compositions. Specifically, BaMn 0.5 Fe 0.5 O 3− 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 CO 2 emissions for hydrogen production