(246e) “Herycnite Cycle” Materials for Pseudo-Isothermal Solarthermal Water Splitting

Muhich, C. L., University of Colorado at Boulder
Ehrhart, B. D., University of Colorado at Boulder
Weston, K., University of Colorado at Boulder
Alshankiti, I., University of Colorado at Boulder
Musgrave, C. B., University of Colorado
Weimer, A. W., University of Colorado at Boulder

Solar thermal water splitting (STWS) is a promising technology for producing hydrogen gas economically, efficiently and cleanly. Two-step, metal oxide based STWS cycles generate H2 by a metal oxide undergoing sequential high temperature reduction and water re-oxidation. The “hercynite cycle”, which is based on iron reduction in a spinel structure, relies on intimate contact between CoFe2O4 and Al2O3 phases in order to form the Co0.33Fe0.66Al2O4 structure needed for STWS redox cycling. In this work we used atomic layer deposition of CoFe2O4 on a nano-scale alumina support to produce the 85% active “hercynite cycle” material. Using this material we carried STWS operating under pseudo-isothermal water splitting (PITWS), where the reduction and oxidation temperatures differed less than 150°C. By combining ALD fabricated “hercynite cycle” materials and PITWS we were able to produce H2 of approximately  400 μmol H2/total g.