Synthesis of novel ferrite foam materials for water-splitting application
R.V. Shende, J.A. Puszynski
South Dakota School of Mines & Technology, US
Keywords: ferrite foam, nanotubular structure, high surface area, water-splitting
Abstract:Globally increasing energy demands with reduced emission of greenhouse gases require the use of more sustainable energy sources. One of the technically viable sustainable energy technologies is based on the thermochemical water-splitting process utilizing redox materials for generation of hydrogen. Though the process has several merits, the two steps that are typically required for water-splitting (low-temperature step) and subsequent regeneration of catalytic material (higher temperature step) make the process less attractive from the point of view of structural integrity and undesirable sintering or grain growth of the redox materials deposited on conventionally used monolithic SiC reactors. These aspects demand newer catalytic materials for more efficient reactors for generating hydrogen from water-splitting reaction with significantly reduced temperature difference between water-splitting and regeneration steps. We report the synthesis of Ferrite foam material with the composition of SnxNiyFe2O4 and its effectiveness on the high-temperature water-splitting reaction. The material was synthesized using a surfactant templating sol-gel approach involving the addition of polymer spheres followed by microwave heating. Specifically, the Sn, Ni and Fe precursors were added in ethanol containing surfactant/polymer microspheres, and the solution was sonicated for several hours. After the addition of propylene oxide, the gel formation was occurred in 5 min. The gel was rapidly heated in an industrial scale microwave furnace to 1100oC and quenched. Powder X-ray diffraction, scanning electron microscopy (SEM), and BET surface area analysis were performed to characterize the catalytic material. X-ray diffraction did not show impure phases associated with carbon containing compounds whereas SEM image as shown in Figure 1 indicated foam like morphology. Further analysis of the foam reveals high aspect ratio nanosize tubular structure, which was consistent throughout the sample matrix. The BET surface area of this foam like material was 156 m2/g, which is six fold higher than for the ferrites conventionally used in water-splitting reaction. The material was then used for thermochemical water-splitting reaction and the results obtained on the synthesis, characterization, and H2 yield during water-splitting reaction will be presented.