Keynote 1: Two-step Solarthermal Water Splitting – The Path Forward

Solar thermal water splitting (STWS) is a method for producing renewable hydrogen from water and concentrated sunlight using energy from the entire solar spectrum to directly drive the splitting reactions and, therefore, providing for high theoretical solar to hydrogen efficiencies.  In two-step STWS, a metal oxide is heated to high temperatures using concentrated sunlight until it reduces, forming a reduced product and O2.  In a second step, H2O re-oxidizes the material to its original state, forming H2.  Various aspects of the operation of this process have been investigated since the 1970’s including the chemistry of the active redox material, which is reducing and oxidizing, the effects of redox operating conditions, and the solar thermal reactors in which the reactions occur. This presentation includes the current understanding and state of the field in each of these aspects and then provides a perspective on important future research directions. A primary focus is a continuous isothermal redox process using robust, low cost, and high productivity iron aluminate active materials.


Alan Weimer

Clark Professor, Chemical and Biological Engineering, University of Colorado