Luminescent and photocatalytic activity of NaGd(MoO4)2:Dy3+/Eu3+ and NaGd(WO4)2:Dy3+/Eu3+ nanorods for efficient sensing and degradation of the antibiotic drug, nitrofurantoin

Abstract

The widespread use of antibiotic medication (nitrofurantoin; NFT) in pharmaceuticals poses serious risks to both human and animal health. In addition, NFT residues can be found in or released into nearby groundwater, rivers, lakes and other surfaces, posing grave threats to the health of living beings. Consequently, the synthesis of high-performance sensors and catalyst materials for the specific and ultra-sensitive detection and removal of NFT from water and food samples is of significant importance for community health and environmental quality. In this study, we designed NaGd(MoO₄)₂:Dy³⁺/Eu³⁺ and NaGd(WO₄)₂:Dy³⁺/Eu³⁺ nanorods through a simple hydrothermal technique and assessed their functional activity for photoluminescence sensing and photocatalytic degradation of NFT. The physicochemical characterization of the prepared nanorods was explored by different analytical and spectroscopic techniques. The photoluminescent properties of NaGd(MoO₄)₂:Dy³⁺/Eu³⁺ showed that it is highly sensitive and exhibits selective sensing against NFT in aqueous solutions. In particular, the emission band at 558 nm showed a noteworthy quenching effect after adding NFT solution to a colloidal solution of the synthesized nanorod. Significantly, NaGd(MoO₄)₂:Dy³⁺/Eu³⁺ exhibited the limit of detection of 0.12 ppm and a quenching constant of 7.35 × 10⁶ M⁻¹ for NFT, which indicates the high selectivity and sensitivity of the prepared nanorod toward NFT. On the other hand, the NaGd(WO₄)₂:Dy³⁺/Eu³⁺ nanorods possessed exceptional photocatalytic activity against the photodegradation of NFT. The obtained UV-Vis spectroscopy results clearly envisage that NaGd(WO₄)₂:Dy³⁺/Eu³⁺ (E_g = 3.42 eV) nanorods could act as a superior photocatalyst than that of NaGd(MoO₄)₂:Dy³⁺/Eu³⁺ (E_g = 4.02 eV) nanorods. The degradation efficiency of NaGd(WO₄)₂:Dy³⁺/Eu³⁺ toward NFT was observed to be ∼96% within 45 min under UV irradiation, and it displayed good stability by monitoring the reusability of the photocatalyst. The improved photocatalytic activity was credited to the increased migration efficiency of the photo-generated electrons and holes.