Controllable synthesis and luminescent properties of hierarchical flowerlike CaMoO4 microspheres

• Well-defined 3D hierarchical flowerlike CaMoO4 microsphere was successfully synthesized.
• The presence of EDTA was considered to be the chelation agent.
• The possible formation mechanism related to nucleation–dissolution–recrystallization governed self-assembly process was proposed.

Well-defined three-dimensional (3D) hierarchical flowerlike calcium molybdate (CaMoO4) microspheres were successfully synthesized via a facile ultrasound-assisted ethylenediaminetetraacetic acid (EDTA) chelation process. The structure and morphology were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and high-resolution transmission electron microscopy (HRTEM). Time-dependent experiments with appropriate intervals have clearly disclosed that the self-assembly process of 3D flowerlike CaMoO4 microspheres is governed by a nucleation–dissolution–recrystallization growth mechanism. Moreover, the nitrogen adsorption–desorption isotherm indicated the presence of mesoporosity in the product. The room temperature photoluminescence (PL) properties of the products were then studied using a spectrophotometer and the samples exhibited green emission peaks centered around 470 nm, 485 nm and 493 nm with 280 nm excitation wavelength.