FTIR CHARACTERIZATION OF SURFACE HYDRATION AND METAL OXYGEN BONDING IN A CERIUM CONTAINING ZINC FERRITE SAMPLE

Abstract

To investigate the lattice-related vibrational features and surface hydration of a single nominal cerium-containing zinc ferrite powder, Fourier transform infrared spectroscopy was used. The specimen was synthesized by an aqueous precipitation method and washed and thermally treated. There are annotations on the reported transmittance spectrum at 3430, 2358, 1620, 1384 and 593 cm⁻¹, and one additional annotation at 450 cm⁻¹ is shown at the lower frequency end of the spectrum. The wide envelope near 3430 cm-1 and the feature close to 1620 cm-1 are both ascribable to the presence of hydrogen-bonded hydroxyl groups at the powder surface and to molecular water. The strong 593 cm-1 band is consistent with the presence of metal–oxygen bonding that will be found in a ferrite material. The 2358 cm-1 signal is tentatively identified as a carbon dioxide atmospheric band and the 1384 cm-1 band is chemically non-specific and may be related to a residual nitrate/carbonate band. The 450 cm⁻¹ annotation is tentative because it is below the quoted acquisition limit of 500 cm⁻¹. Interpretation is limited to one specimen and does not yield a substitution fraction, ratios of cation occupancy or of the oxidation states. This leads to the identification of a hydrated oxide interface and to the identification of possible vibrational assignments from the possible questions on the composition and measurement. The results are used as a qualitative basis for further studies of surface functionalization and any claims made about sensor performance needs to be validated at the device level.