Preparation, characterization and emission of Na3-3xLnxFe2(PO4)3 (Ln = Eu, Tb; 0 ≤ x ≤ 0.1 mol %) and photocatalytic activity of Na3Fe2(PO4)3.

Rare earth doped compositions Na 3-3 x Ln x Fe 2 (PO 4) 3 (x = 0, 0.025, 0.05, 0.075 and 0.1) were prepared by ion-exchange method using Na 3 Fe 2 (PO 4) 3 and LnCl 3 (Ln = Eu and Tb). Pristine Na 3 Fe 2 (PO 4) 3 was obtained by ethylene glycol assisted gel burning procedure. The phase characterization was performed by powder X-ray diffraction (XRD). All the compositions were well crystalized in monoclinic lattice. The FE-SEM images and elemental mapping were obtained. The infrared and Raman profiles of all-compounds were dominated by the bands owing to the (PO 4) units. Investigation on photoluminescence emission and excitation spectra of Ln3+ (Ln = Eu, Tb) were carried out. The excitation spectra of Na 3-3 x Ln x Fe 2 (PO 4) 3 (Ln = Eu and Tb) gave intensive band at 256 (370) nm for Eu (Tb) doped phosphors. The photoluminescence emission spectra of Ln3+ (Ln = Eu, Tb) were carried out. The emission spectra of these composition were characterized by f -f transitions corresponding to 613 (5D 0 →7F 2) for Eu and 543 (5D 4 →7F 5) for Tb doped compositions. The maximum emission intensity for Eu (Tb) doped phosphors was found at x = 0.075 (0.05). The analysis of CIE and CCT values of all prepared phosphors were also carried out. Decay curves were analyzed in detail. The visible-light photo-catalytic activity of parent Na 3 Fe 2 (PO 4) 3 was examined against decomposition of methylene blue and methyl orange dyes. Parent Na 3 Fe 2 (PO 4) 3 exhibits good efficiency against MB (≈94.5 %) and moderate efficiency against MO (≈64 %) in 180 min of visible light irradiation. Scavengers' experiments were carried to identify the active species during photodegradation. Na 3 Fe 2 (PO 4) 3 : Eu/Tb doped Na 3 Fe 2 (PO 4) 3 ; Photocatalytic and luminescence investigation. [Display omitted] • Gel burning method was used to obtain Na 3 Fe 2 (PO 4) 3 , while Ln3+ doped compositions were prepared using ion-exchange method. • The PLE, emission, CIE colour coordinates, colour purity, life times and CCT values are deduced for Eu3+ and Tb3+-doped NFPO. • The photocatalytic activity of NFPO was studied against the degradation of methylene-blue (MB) and methyl orange (MO) dyes. [ABSTRACT FROM AUTHOR]