Jacob Schliesser

Magnetic and Thermodynamic Properties of Nanosized Zn Ferrite with Normal Spinal Structure Synthesized Using a Facile Method

Normal spinel zinc ferrite (ZnFe2O4) nanoparticles (NPs) with zero net magnetization were synthesized by a facile coprecipitation method in which two kinds of organic alkali, namely, 1-amino-2-propanol (MIPA) and bis(2-hydroxypropyl)-amine (DIPA), were used. The diameters of the ZnFe2O4 NPs were determined to be about 7 and 9 nm for samples prepared with MIPA and DIPA, respectively, and the normal spinel structure was confirmed by the magnetic property measurement at room temperature and the temperature dependence of the direct current magnetization. These results are different from those reported in the literature, where ZnFe2O4 NPs show a nonzero net magnetization. The heat capacity of the ZnFe2O4 NPs synthesized using DIPA was measured using a physical property measurement system in the temperature range from 2 to 300 K, and the thermodynamic functions were calculated based on the curve fitting of the experimental heat capacity data. The heat capacity of the ZnFe2O4 NPs was compared with that of a nanosized (Zn(0.795)Fe(0.205))[Zn(0.205)Fe(1.795)]O4 material studied in the literature, indicating that the Debye temperature of the present sample is more comparable with that of the bulk ZnFe2O4 reported by Westrum et al.

Synthesis and Thermodynamics of Porous Metal Oxide Nanomaterials

Porous metal oxide nanoparticles is a new class of material of great scientific and technological importance with a wide range of applications. In this article, we briefly review the synthetic methods and thermodynamic properties of such materials. We compare and summarize common synthetic routes of such materials including solid-state, solution- phase (co-precipitation, sol-gel, microemulsion, solvothermal/hydrothermal, non-aqueous), and vapor-phase methods. As for the thermodynamics of porous metal oxide nanoparticles, we review experimental determinations, mainly by calorime- try, on surface and interfaces energetics. The interplay among particle size, surface area, morphology, surface stabilizer, phase stability, and redox potentials is discussed.