ANALYSIS OF THE THERMOCHEMICAL REDUCTION OF 3D-ORDERED MACROPOROUS CERIA-ZIRCONIA FOR FUEL PRODUCTION APPLICATIONS

摘要

In terms of methods to sustainably convert solar energy into useful, transportable fuels, harnessing the sun's heat to make fuel— solar thermochemical fuel production—has great potential to be transformative. Unfortunately, the direct decomposition of the abundant feedstocks H2O and CO2 into either useful fuel, H, or a fuel precursor, CO + H, is not possible due to the extreme temperatures (>2500 °C) required for generation of an acceptable amount of product.This problem can be circumvented by splitting the decomposition into two steps via the use of a cerium oxide (CeO2) catalyst. In the first step, CeO2 is reduced at high temperatures (1100 to 1800 °C) in an inert gas, generating oxygen gas and CeO_(2-δ) (1). The second step is a lower temperature (~500 to 1000 °C) fuel production step, wherein H2O and/or CO2 gas is allowed to flow over Ce0.5. During this step, the CeO_(2-δ) strips oxygen from the H2O and/or CO, producing H2 (2) and/or CO (3). The CeO2 is regenerated for continued cycling. Improvements are needed to achieve efficiencies that will allow the CeO2 cycle to compete with other methods for synthesizing sustainable fuels.