Microwave solution route to ceramic ZnAl₂O₄ nanoparticles in 10 minutes: inversion and photophysical changes with thermal history

Abstract

Within 10 minutes microwave synthesis using metal complexes can form crystalline ZnAl2O4 nanoparticles with significant inversion.

Size-Tunable Alumina-Encapsulated Sn-Based Phase Change Materials for Thermal Energy Storage

“…The narrow scan of Al 2p without Ar etching (on the surface, 0 nm) is shown in Figure 3b, in which the Al 2p peak was deconvoluted to two separated peaks located at 72.0 eV (blue) and 74.2 eV (red), representing tetrahedral Al 3+ and octahedral Al 3+ , respectively. 23 The formation of these two different Al 3+ species may be caused by the different local oxygen abundance in the SnO 2 @Al 2 O 3 and the effect of Sn atoms. This phenomenon was also found previously in some Al-related spinel structures.…”

“…Figure c,d shows the narrow scan of Al 2p peak and Sn 3d peaks at the position of different Ar etching depths in SnO 2 @Al 2 O 3 spheres. The narrow scan of Al 2p without Ar etching (on the surface, 0 nm) is shown in Figure b, in which the Al 2p peak was deconvoluted to two separated peaks located at 72.0 eV (blue) and 74.2 eV (red), representing tetrahedral Al 3+ and octahedral Al 3+ , respectively . The formation of these two different Al 3+ species may be caused by the different local oxygen abundance in the SnO 2 @Al 2 O 3 and the effect of Sn atoms.…”

Probing the validity of the spinel inversion model: a combined SPXRD, PDF, EXAFS and NMR study of ZnAl2O4

“…Previous studies have found that the inversion degree depends significantly on the thermal history of the sample, which in general decrease with increasing temperature. 7,21,[49][50][51] The fact that the degree of inversion is dependent on thermal history has been reported for other spinel systems such as ZnFe2O4 and MgAl2O. 52,53 However, in most of these studies additional defects such as interstitials and vacancies are not taken into account.…”

Preparation of mesoporous ZnAl2O4 nanoflakes by ion exchange from a Na-dawsonite parent material in the presence of an ionic liquid

“…Zinc aluminate (ZnAl 2 O 4 ) spinel is a well-known wide band gap semiconductor (E g ¼ 3.8 eV) 1 ceramic material with optomechanical property, which has been extensively studied as a catalyst and catalyst support, [2][3][4] transparent conductor, 5 dielectric material, 6 optical material 7 and sensor 8 due to its high thermal stability, low surface acidity and high mechanical resistance. 9 Several methods, for example, the solid statereaction or ceramic method, 10 wet chemical routes, 11,12 the sol-gel method, 13,14 the hydrothermal method, 15 the solvothermal method, 16 the plasma method, 17 combustion in an aqueous solution 18 and molten salt synthesis 19 etc., have been applied for the preparation of ZnAl 2 O 4 spinel. However, to date, it is still a challenge to synthesize 2D or 3D ZnAl 2 O 4 spinel nanostructures via a solution route.…”