Sol–gel synthesis of silica composited flower-like microspheres using trivalent europium tartrate as a template

Abstract Silica composited flower-like microspheres were synthesized by a facile sol–gel synthesis method using trivalent europium tartrate (Eu 3+ -TTA) as the template. Fourier transform infrared spectra (FT-IR) X-ray photoelectron spectroscopy (XPS), X-ray diffraction analyses (XRD), Energy-dispersive X-ray (EDS) spectroscopy, scanning electron microscopy (SEM), thermogravimetry-differential thermal analysis (TG-DTA) were employed to characterize the composition, structure, and morphology of the products. The microspheres were composed of nanosheets as petals. Size of the spherical shape varied with the amount of tetraethoxysilane (TEOS) addition. As the addition of TEOS decreased the diameters of microspheres increased, and it was proven that Eu 3+ ions existed in the form of Si–O–Eu covalent bond. Furthermore, a sol–gel templated mechanism is proposed to interpret the formation process of flower-like microspheres shape. The hollow-liked microspheres were obtained by a following calcination process. In addition, photoluminescent emission of the products was further discussed, which indicated that Eu 3+ ions exhibit characteristic luminescent emissions and their luminescent intensity after calcination is higher than that of as-synthesized sample. Graphical abstract The silica composited microspheres with flower-like shape were prepared successfully by a facile sol–gel synthesis method using trivalent europium tartrate (Eu 3+ -TTA) as a template. A sol–gel templated mechanism was proposed to interpret the formation process of flower-like shape microspheres. During this process, Eu 3+ -tartrate was supposed to form supramolecular template by self-assembly and coordinate with silica oligomer by means of intermolecular interactions. Furthermore, it was indicated that Eu 3+ exhibits strong characteristic luminescence in this system.