(217fm) Isothermal Water Splitting Using The Two-Step Redox “Hercynite Cycle”

Muhich, C. L., University of Colorado at Boulder
Evanko, B. W., University of Colorado at Boulder
Weston, K., University of Colorado at Boulder
Lichty, P., University of Colorado
Liang, X., University of Colorado at Boulder
Musgrave, C. B., University of Colorado Boulder
Weimer, A. W., University of Colorado Boulder

The use of hydrogen as a renewable fuel has been stymied by our inability to produce it cleanly and economically. Solar thermal water splitting (STWS) cycles have long been recognized as a desirable means of generating sustainable H2 from water and sunlight. Two-step, metal oxide based STWS cycles generate H2 by a metal oxide undergoing sequential high temperature reduction and water re-oxidation. The temperatures swings between reduction and oxidation steps long thought necessary for STWS has stifled STWS’s overall efficiency and materials robustness due to thermal and time losses during the frequent heating and cooling of the metal oxide. Here, we show that these temperature swings are unnecessary, and that isothermal water splitting (ITWS) exhibits more favorable H2 production capacity and reaction rates (167.4 µmol H2/gram and 1.34 µmol H2/gram/s at 1450 oC) than traditional temperature swing water splitting. ITWS opens the door for more simple, robust and efficient renewable H2 production.  This presentation will summarize the requisite thermodynamics and experimental results for redox water splitting using the ”hercynite cycle” .