Sol-Gel Synthesis of Nanocrystalline Ni-Ferrite and Co-Ferrite Redox Materials for The rmochemical Production of Solar Fuels

摘要

In this contribution, we report the synthesis and characterization of Ni_xFe_(3-x)O_4 and Co_xFe_(3-x)O_4 redox nanomaterials using sol-gel method. These materials will be used to produce solar fuels such as H_2 or syngas from H_2O and/or CO_2 via solar thermochemical cycles (STCs). For the sol-gel synthesis of ferries, the Ni, Co, Fe precursor salts were dissolved in ethanol and propylene oxide (PO) was added dropwise to the well mixed solution as a gelation agent to achieve gel formation. Freshly synthesized gels were aged, dried, and calcined by heating them to 600℃ in air. The calcined powders were characterized by powder x-ray diffractometer (XRD), BET surface area, as well as scanning (SEM) and transmission (TEM) electron microscopy. Their suitability to be used in STCs for the production of solar fuels was assessed by performing several reduction/re-oxidation cycles using a thermogravimetric analyzer (TGA).