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

Abstract

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 (R² = 0.99104) and the smallest limit of detection (LOD = 0.12 μM) 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 × 10⁻⁴ mol L⁻¹ (close to 4 × 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⁺.