hydrogen, thermochemical water-splitting, core-shell, Ni-ferrite/Y2O3
During thermochemical water-splitting process for hydrogen generation,ferritenanoparticles undergo significant grain growth that reduces their surface area and affect the porous morphology. Consequently, hydrogen volume generation diminishes with increase in thermochemical cycles. In order to mitigate the grain growth, we have encapsulated the ferrite nanoparticles with porous shell of thermally stable ceramic materials. In this study, Ni-ferrite nanoparticles were synthesized using the sol-gel method and further utilized to prepare core-shell nanoparticles with Y2O3. Core-shell Ni-ferrite/Y2O3 nanoparticles were loaded in Inconel packed-bed reactor and five consecutive thermochemical cycles were performed at 900o – 1100 oC for hydrogen generation. The results indicated steady hydrogen volume generation in multiple thermochemical cycles. In addition, significant grain growth mitigation was observed in core-shell ferrite nanoparticles as compared to ferrite nanoparticles during thermochemical processing. Grain growth and morphological properties of the core-shell nanoparticles before and after the thermochemical water splitting reaction were investigated using BET surface area analysis, X-Ray diffraction, and scanning and transmission electron microscopy. In-depth characterization of the core-shell nanoparticles, grain growth mitigation and the results obtained on hydrogen volume generation from thermochemical water-splitting using ferrite and core-shell ferrite nanoparticles will be presented.