The morphological stability and fuel production of commercial fibrous ceria particles for solar thermochemical redox cycling

Implementation of the solar thermochemical ceria redox cycle to split water and carbon dioxide depends in part on the morphological stability of a porous ceria substrate and the ability to acquire porous substrate in high volume. Here we evaluate the evolution of morphology and fuel production of ceria particles formed of fibers in a commercially relevant manufacturing process. The particles are evaluated over 1000 CO₂-splitting cycles (56 h) at 1773 K followed by sixteen temperature-swing cycles (5.7 h) with oxidation at 1073 K. New particles are 78% porous with a specific surface area of 0.14 m² g⁻¹ and a grain size of 3.7 μm. During isothermal cycling, the morphology stabilized after 500 cycles (28 h) to 73% porosity, a surface face 0.08 m² g⁻¹ and a grain size of 8 μm. The stabilized particles retained 89% of the peak cycle average rate of CO production. During temperature-swing cycling, the specific surface area decreased to 0.06 m² g⁻¹. The mass-produced fibrous structures have adequately stable morphologies to produce fuel production performance similar to less scalable (lab-scale) ceria structures of similar pre-cycling surface area.