Solar Thermochemical Water Splitting Processing (STWS) is a promising technology for producing renewable H2
. A metal oxide, such as hercynite (FeAl2
), is first reduced with high temperature concentrated sunlight to produce O2
. Then, the reduced material is exposed to steam to re-oxidize it and produce H2
. Low O2
partial pressure is required to drive the reduction reaction. An intriguing potentially highly efficient process is the recycle of inert sweep gas at near atmospheric pressure using a high temperature O2
ionic transport membrane (ITM), since the recycled gas is already at the required high temperature. In this work, we present preliminary experimental results for hercynite reduction using a TGA and separately the removal of O2
from 1% O2
/inert down to ppm levels using a laboratory high temperature ITM. The impact of separation energy requirements is evaluated for the overall solar to H2
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