Iron Aluminate Reticulated Porous Ceramic Fabrication for Use in Solar Thermochemistry

Solar thermochemistry involves cycling redox materials to split CO₂ and H₂O into CO and H₂, which can then be converted into hydrocarbon fuels and syngas. This process occurs at high temperatures (~1500ºC), so to directly irradiate the active material, a fixed form must be used as opposed to powder. While many use ceria as an active redox material, we propose that iron aluminate offers substantial benefits when compared with ceria, and thus has the potential to increase the efficiency of the process.

One advantage of using iron aluminate is its high productivity under isothermal or near-isothermal operating conditions. Ceria requires a temperature swing from ~1500ºC for reduction to ~900ºC for oxidation to effectively split water, which causes heat loss and decreases process efficiency. Iron aluminate has demonstrated productivity substantially higher than that of ceria while operating isothermally at 1400ºC with a slight pressure-swing (Tran et al., 2023) and has demonstrated thermal stability over 2000 redox cycles.

To compare iron aluminate’s water and CO₂ splitting capacity with that of ceria, we have developed a novel process for fabricating iron aluminate reticulated porous ceramics (RPCs). RPCs are solid, porous structures. Their mechanical stability and porosity make them ideal candidates for solar thermochemistry because they are robust through cycling and optimize volumetric absorption of radiation. Fabricated iron aluminate RPCs will be demonstrated in the ETH Zurich solar reactor system for water and CO₂ splitting using concentrated sunlight.

Acknowledgement: EERE DE-EE0010729

References:

Tran, J., K.J. Warren, D. Mejic, R.L. Anderson, L. Jones, D.S. Hauschulz, C. Wilson and A.W. Weimer, “Pressure-enhanced performance of metal oxides for thermochemical water and carbon dioxide splitting,” Joule, 7, 1759-1768 https://doi.org/10.1016/j.joule.2023.07.016 (2023)