Controlled Synthesis of Calcium Tungstate Hollow Microspheres via Ostwald Ripening and Their Photoluminescence Property

Abstract

Nearly monodispersed CaWO4 hollow microspheres with controlled diameters were successfully prepared by a facile one-step hydrothermal method using CaCl2, Na2WO4, and sodium dodecyl sulfate (SDS) as the starting reaction reagents and distilled water as solvent. The crystal structure, morphology, macroporous and photoluminescence properties of the as-synthesized products are characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, selected-area electron diffraction, nitrogen adsorption−desorption isotherm technique, and fluorescence spectrometer. The hollow microspheres have an average diameter of 2.2 μm and hollow interior of 0.5−1 μm. The shell is consisting of numerous nanoparticles 45 nm in diameter. The effects of SDS amount, pH value, concentrations of reaction reagents, and reaction durations have been studied systematically. The results indicate that a certain SDS amount plays a key important role in the final formation of hollow microspheres. It is also fo...