Formation of FeMoO4 hollow microspheres via a chemical conversion-induced Ostwald ripening process

Abstract

FeMoO₄ hollow microspheres were prepared via a template-free hydrothermal method using FeCl₂ and Na₂MoO₄ as the starting reaction reagents and distilled water as the solvent. The crystal structure, morphology and UV-vis reflection property of the as-synthesized products are characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy and UV-vis diffuse reflectance spectroscopy. The hollow microspheres have diameters ranging from 3 to 5 μm, hollow interiors of ∼2.5 μm and the shell is constructed by numerous nanoparticles with sizes of 100–200 nm. The effects of reaction temperature, concentration of reaction reagents and reaction times have been studied. The formation mechanism of the FeMoO₄ hollow microspheres is related to the chemical conversion-induced Ostwald ripening process.