Sr- and Mn-doped LaAlO3−δ for solar thermochemical H2 and CO production

Abstract

The increasing global appetite for energy within the transportation sector will inevitably result in the combustion of more fossil fuel. A renewable-derived approach to carbon-neutral synthetic fuels is therefore needed to offset the negative impacts of this trend, which include climate change. In this communication we report the use of nonstoichiometric perovskite oxides in two-step, solar-thermochemical water or carbon dioxide splitting cycles. We find that LaAlO₃ doped with Mn and Sr will efficiently split both gases. Moreover the H₂ yields are 9× greater, and the CO yields 6× greater, than those produced by the current state-of-the-art material, ceria, when reduced at 1350 °C and re-oxidized at 1000 °C. The temperature at which O₂ begins to evolve from the perovskite is fully 300 °C below that of ceria. The materials are also very robust, maintaining their redox activity over at least 80 CO₂ splitting cycles. This discovery has profound implications for the development of concentrated solar fuel technologies.