Publication: Novel perovskite materials for thermal water splitting at moderate temperature
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2019-09-06
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Wiley
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Abstract
Materials with the formula Sr2CoNb1−xTixO6−δ (x=1.00, 0.70; δ=number of oxygen vacancies) present a cubic perovskite-like structure. They are easily and reversibly reduced in N2 or Ar and re-oxidized in air upon heating. Oxidation by water (wet N2), involving splitting of water at a temperature as low as 700 °C, produces hydrogen. Both compounds displayed outstanding H2 production in the first thermochemical cycle, the Sr2CoNb0.30Ti0.70O6−δ material retaining its outstanding performance upon cycling, whereas the hydrogen yield of the x=1 oxide showed a continuous decay. The retention of the materials’ ability to promote water splitting correlated with their structural, chemical, and redox reversibility upon cycling. On reduction/oxidation, Co ions reversibly changed their oxidation state to compensate the release/recovery of oxygen in both compounds. However, in Sr2CoTiO6−δ, two phases with different oxygen contents segregated, whereas in Sr2CoNb0.30Ti0.70O6−δ this effect was not evident. Therefore, this latter material displayed a hydrogen production as high as 410 μmolurn:x-wiley:18645631:media:cssc201901484:cssc201901484-math-0001 g−1perovskite after eight thermochemical cycles at 700 °C, which is among the highest ever reported, making this perovskite a promising candidate for thermosolar water splitting in real devices.
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Hydrogen generation, Perovskite phases, Solar fuel, Thermochemical cycle, Water splitting
Bibliographic citation
Azcondo, M. T., Orfila, M., Marugán, J., Sanz, R., Muñoz-Noval, Á., Salas-Colera, E., Ritter, C., García-Alvarado, F., & Amador, U. (2019). Novel Perovskite Materials for Thermal Water Splitting at Moderate Temperature. ChemSusChem, 12(17), 4029-4037.