Study of a Magnetically Stabilized Porous Structure for Thermochemical Water Splitting via TGA, High-Temperature-XRD, and SEM Analyses

Abstract

Sintering of metal particles at high temperature in thermochemical looping processes, such as the iron-based looping process, dramatically reduces their reactivity. During the sintering process, metal particles lose their chemically active surface area, typically within only a few oxidation and reduction cycles. To cope with this problem, a uniform external magnetic field is applied to a fluidized mixture of iron and silica particles to form an organized structure of magnetic iron chains. In this study, reaction kinetics of the magnetically stabilized porous structure during oxidation has been examined using thermogravimetric analysis (TGA). High temperature X-ray diffraction (HT-XRD) has been performed in situ to determine at which temperatures structural changes occur. Scanning electron microscopy (SEM) has been performed on samples, both before and after many cycles, to show the morphological changes that occur within the sample. TGA results demonstrate that the magnetically stabilized porous structure has excellent stability and reactivity at high reaction temperatures. These results indicate that this structure is suitable for many industrial and chemical processing applications involving high temperature, such as synthetic fuel production.