Hydrothermal synthesis of Eu3+-doped BaMoO4 fluorescent probe for the selective detection of Fe3+ ions

Water-dispersible Eu3+-doped BaMoO4 phosphors with a morphology of monodisperse uniform elongated octahedra are prepared using a hydrothermal method in this paper. The phosphors are used to detect Fe3+ ions in aqueous solution because of the fluorescence quenching caused by the competitive adsorption between the Fe3+ ions and Eu3+ ions. A modified Stern-Volmer formula is used to describe the fluorescence quenching. The best fitting curve (R-2 = 0.99104) and the smallest limit of detection (LOD = 0.12 mu M) are obtained when the doping concentration of Eu3+ is 1 mol%. Furthermore, various cations are added to the aqueous solution to verify the selective detection of Fe3+ ions. Besides, it is interesting that the phosphor is renewable because the photoluminescence (PL) intensity can recover to 94% by adding NH4F to the aqueous solution after detecting Fe3+-ions. Finally, the Eu3+-doped BaMoO4 phosphor is used to detect Fe3+ in a lake water sample, and the calculated Fe3+ concentration is 3.6 x 10(-4) mol L-1 (close to 4 x 10(-4) mol L-1 measured using ICP). Our investigation suggests that the Eu3+-doped BaMoO4 phosphor is an efficient and renewable fluorescent probe for the selective detection of Fe3+.