Facile preparation of 3D interconnected macroporous CeF3

Abstract

CeF3 is largely used due to its technological importance for applications in various domains such as photonics, sensors, energy and catalysis and its nanostructuration represents a real challenge. In this paper, we report on the novel and environmentally friendly synthetic route of monodisperse CeF3 nanoparticles (NP) with a diameter of about 10 nm and a high surface area (≈130 m2 g−1) by a surfactant-free aqueous precipitation route at room temperature (yield ≈ 90%). The dispersion of the NP as a stable colloidal suspension allows to prepare for the first time 3D interconnected macroporous CeF3 through the assembly of as-prepared NP and home-made poly(methyl methacrylate) (PMMA) beads as template. These Organized Porous Inorganic Fluorides (OPIF) materials have been deeply characterized at different synthesis stages by means of powder X-ray diffraction (XRD), N2 sorption, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) analyses. CeF3 OPIF present a macroporosity (pore diameter ≈ 200 nm) as well as well as intergranular mesoporosity emerging from the voids between the CeF3 NP (DTEM ≈ 7 nm) composing the OPIF walls resulting in a surface area of 33 m2 g−1. The thermal stability under nitrogen of the CeF3 crystal structure is increased for the 3D interconnected macroporous materials in comparison with the NP as the CeF3 crystal structure remains stable until 550 °C for CeF3 OPIF and only 400 °C for CeF3 NP. Finally, the porous structuration of CeF3 materials considerably slows down the crystallite growth during thermal treatment under nitrogen. The crystallite size of CeF3 NP constantly increases from 10 nm (120 °C) to 30 nm (420 °C). At the opposite, the crystallite size of CeF3 OPIF remains unchanged until 460 °C (17 nm).