(400d) Synthesis of Ferrite/ZrO2/YSZ Core-Shell Nanoparticles for H2 Generation From Thermochemical Water-Splitting Reaction

H₂ is a green fuel with maximum energy density as compared with the fossil fuels. Thermochemical water-splitting reaction was performed using sol-gel derived Ni-ferrite materials at water-splitting and regeneration temperatures of 700^o-1100^oC. After water-splitting reaction, the ferrite material was recovered and characterized using x-ray diffraction, scanning electron microscopy (SEM) and BET surface area analyzer. Although no change in phase composition was observed, a significant increase in grain size and decrease in specific surface area was noticed. When ferrite materials were subjected to thermochemical water-splitting, significant sintering and grain growth was observed that led to decrease in H₂ volume generation during multiple thermochemical cycling operation. To address this issue, thermal stabilization of ferrite material was investigated by performing the synthesis of core-shell nanoparticles where sol-gel derived Ni-ferrite formed a core within ZrO₂/YSZ (Yttria-stabilized Zirconia) shell. The synthesis of ferrite/ZrO₂/YSZ was accomplished using micro-emulsion technique involving the use of two surfactants. In addition, Ni-ferrite/ZrO₂/YSZ powdered material was also prepared using a vortex mixer. These materials were analyzed using SEM, XRD and BET surface area analyzer. The H₂ generation ability of these ferrite nanomaterials was investigated by performing five consecutive thermochemical cycles in the Inconel packed-bed reactor where water-splitting and regeneration were carried out at 700-900^oC and 1100^oC, respectively. The use of ZrO₂/YSZ as grain growth inhibitor or as a shell material in core-shell nanoparticles was affected the H₂ volume generation. The results obtained on grain growth mitigation, core-shell nanostructures and H₂ volume generation from thermochemical water-splitting reaction will be presented in detail.