Hollow Al2O3 spheres prepared by a simple and tunable hydrothermal method

Abstract

Hollow nanostructures are of great interest in many current and emerging areas of technology. In this paper, uniform hollow spheres of alumina were successfully synthesized by a simple and tunable hydrothermal treatment and calcination process. The effects of preparation parameters on the properties of the spheres, for example, surface area, particle diameter and thickness of the shell, were explored. The microstructure, morphology, and chemical composition of the resulting materials were characterized by X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), thermogravimetry, ¹³C solid state NMR, and N₂ adsorption–desorption techniques. Based on the characterizations of as-prepared products, a new formation mechanism of the alumina hollow spheres was proposed.