Zinc Ferrite Nanoparticles: Unusual Growth Mechanism for Size‐Dependent Properties

Abstract

Herein, non‐stoichiometric zinc ferrite nanoparticles, Zn0.86Fe2.14O4+δ,with grain sizes of being smaller than 11 nm were successfully prepared by varying the hydrothermal reaction duration and temperature. The influence of reaction temperature and time on the grain size of zinc ferrite nanoparticles was investigated. Non‐stoichiometric zinc ferrite nanoparticles underwent distinct processes at different reaction temperatures: at 200 °C, the growth mechanism follows an Ostwald ripening model with activation energy 124.7 kJ/mol, while at 120 °C, the particle growth is governed by aggregation and coalescence, Ostwald ripening mechanism with the activation energy 27.5 kJ/mol and digestive ripening process.The abnormal growth behavior of zinc ferrite nanoparticles is completely different from previous reports on the oxides. Detailed analysis of XPS, XRD, FT‐IR and Mössbauer spectra revealed that the presence of rich iron oxides on the surface of nanoparticles is responsible to the non‐stoichiometry. Moreover, unit cell volume and magnetic property of non‐stoichiometric zinc ferrite exhibited two extremum as the increase of grain size, which was closely related to the grain size‐dependent structure changing. The unusual growth behavior and the size dependent structure and property changes of non‐stoichiometric zinc ferrite nanoparticles reported in this work may be beneficial to guide the future development of magnetic materials.

F-doped zinc ferrite as high-performance anode materials for lithium-ion batteries

“…According to previous reports, smaller particle size can increase the specific capacity of anode material as well as reduce the diffusion path of ions, leading to the improved kinetic velocity of the material. 18 The HRTEM image of ZFO (Fig. 2c) exhibits the lattice spacings of 0.303 and 0.261 nm, which corresponded well with the inter-planar distances of (220) and (311) crystal planes of the ZFO cubic structure.…”

“…It has been proved that smaller particle sizes can shorten the ion transport distance, increase the contact area and accelerate the lithium-ion transport speed, thereby enhancing the specific capacity. 18,19 In addition, very recently, anions doping has been considered an effective technique to improve the conductivity of battery anode materials. 20,21 For example, fluorine-doped materials exhibit a higher reversible specific capacity than the pristine materials.…”

Facile Synthesis of Polyindole/Ni1–xZnxFe2O4(x= 0, 0.5, 1) Nanocomposites and Their Enhanced Microwave Absorption and Shielding Properties

“…This is due to the larger size of the Zn 2+ ions (0.83 Å) compared to the Ni 2+ ions (0.78 Å) . However, the exceptionally high crystalline size of ZF nanoparticles is attributed to the sample’s tendency to fuse at high temperatures and can be explained by an aggregative growth mechanism. , As shown in Figure , it is seen that both the characteristic amorphous peaks of PIN and the signature peaks for pristine ferrite nanoparticles appear in the diffraction patterns of PIN/Ni 1– x Zn x Fe 2 O 4 ( x = 0, 0.5, 1) nanocomposites. This suggests that nanoparticles have been successfully incorporated into the PIN matrix.…”

Understanding the Doping Chemistry of High Oxidation States in Scheelite CaWO4 by Hydrothermal Conditions

“…Similar observations have been reported for many other oxide nanocrystals. 38,39 From the HRTEM images of the selected nanocrystals (insets of Figure S4), one can see that the interplanar spacing between adjacent lattice fringes was 0.312, 0.311, 0.311, 0.311, and 0.312 nm for SS-10, K-200-10, K-160-10, NH 4 -200-10, and NH 4 -160-10 samples, respectively, which are close to the values of 0.312, 0.311, 0.311, 0.311, and 0.311 nm for the (112) plane calculated by Rietveld refinements, respectively, but slightly larger than that (0.310 nm) observed for CaWO 4 (JCPDS card no. .…”