Synthesis and characterization of Ni 1− xZn xFe 2O 4 spinel ferrites from tailored layered double hydroxide precursors

Abstract

In this paper, a series of pure Ni 1 − x Zn x Fe 2O 4 (0 ≤ x ≤ 1) spinel ferrites have been synthesized successfully using a novel route through calcination of tailored hydrotalcite-like layered double hydroxide molecular precursors of the type [(Ni + Zn) 1 − x − y Fe y 2+Fe x 3+(OH) 2] x+ (SO 4 2−) x/2 · mH 2O at 900 °C for 2 h, in which the molar ratio of (Ni 2+ + Zn 2+)/(Fe 2+ + Fe 3+) was adjusted to the same value as that in single spinel ferrite itself. The physico-chemical characteristics of the LDHs and their resulting calcined products were investigated by powder X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS) and Mössbauer spectroscopy. The results indicate that calcination of the as-synthesized LDH precursor affords a pure single Ni 1 − x Zn x Fe 2O 4 (0 ≤ x ≤ 1) spinel ferrite phase. Moreover, formation of pure ferrites starting from LDHs precursors requires a much lower temperature and shorter time, leading to a lower chance of side-reactions occurring, because all metal cations on the brucite-like layers of LDHs can be uniformly distributed at an atomic level.