(690a) A Comparative Assessment of Sol-Gel and Solid State Syntheses Derived Redox Materials for H2 Production Via Thermochemical Water-Splitting Process

Redox materials of the type M_1xM_2yFe₂O₄ (M₁ or M₂ = Zn, Mn, Co, Ni) were prepared by the solid state and sol-gel syntheses routes. In the solid state synthesis route, metal oxide precursors were mixed in the required amounts in water and ball milled for 36 hours. Resultant powered material was calcined in air at higher temperatures to achieve the desired phase formation. In the sol-gel synthesis approach, metal salt precursors were sonicated in ethanol and gel formation was achieved using propylene oxide. The gel was aged, dried and finally calcined in air. The solid state diffusion properties of these redox ferrites were studied using the variable temperature impedance spectroscopy whereas the morphological properties were investigated using scanning/transmission electron microscopy (SEM/TEM), powdered X-ray diffraction (XRD), and Brunner-Emmett-Teller (BET) specific surface area analyzer. A solid state or sol-gel derived redox material was loaded inside a continuous Inconel tubular reactor and thermochemical water-splitting reaction was performed at isothermal conditions. Materials syntheses, characterization and H₂ volume generation over multiple thermochemical cycles will be presented.