Multi-Step Water Splitting with Mn-Ferrite/Sodium Carbonate System 1999-01-2670

Multi-step water splitting with Mn-ferrite(MnFe₂O₄)/sodium carbonate(Na₂CO₃) system accompanying endothermic reaction was investigated for converting solar energy into chemical energy. This water splitting is caused by the oxidation-reduction of manganese ion in the Mn-ferrite. Multi-water splitting with MnFe₂O₄/Na₂CO₃ system was consisted of three steps. The first step was hydrogen generation at 1073K. The second step was oxygen release at 1273K. The third step was Na₂CO₃ reproduction at 873K. The mechanism of multi-water splitting has been considered by XRD, chemical analysis of colorimetry and back titration. The temperature range 873 to 1273K is quite lower than those studied on the solar furnace reaction (O₂ releasing step) in two-step water splitting (1500-2300K). This lower temperature range would permit further progress in converting the direct solar energy into chemical energy.