Sm3+/Eu3+ Co-doped AgGd(MoO4)2 and AgGd(WO4)2: Multifunctional platforms for luminescent sensing of MnO4− and amoxicillin degradation in water

Abstract

The accumulation of industrial contaminants in aquatic environments, particularly metal ions and organic pollutants, poses significant risks to human health and the ecosystem globally. This has led to the development of multifunctional nanoparticles with dual capabilities: luminescent detection and photocatalytic degradation of hazardous contaminants. In this study, we present the development of Sm³⁺/Eu³⁺ co-doped AgGd(MoO₄)₂ and AgGd(WO₄)₂ (Sm³⁺ = 5 %, Eu³⁺ = 7 %) nanomaterials, synthesized via a hydrothermal method, and assessed their performance in luminescence-based detection of MnO₄⁻ anions and photocatalytic degradation of antibiotics in water. The luminescent properties of AgGd(MoO₄)₂:Sm³⁺/Eu³⁺ demonstrated exceptional sensitivity and selectivity for detecting MnO₄⁻ anions in aqueous solutions, with a significant quenching of the emission band at 620 nm upon the introduction of varying concentrations of MnO₄⁻. The nanosensor achieved limit of detection of 0.43 ppm and exhibited a Stern-Volmer (K_sv) quenching constant of 3.61 × 10⁴ M⁻¹ for MnO₄⁻ anions, showcasing its excellent selectivity and sensitivity toward MnO₄⁻ detection. Additionally, AgGd(WO₄)₂:Sm³⁺/Eu³⁺ nanoparticles exhibited superior photocatalytic activity in the degradation of amoxicillin (AMX) in an aqueous environment. UV–Vis spectroscopy data suggested that the AgGd(WO₄)₂:Sm³⁺/Eu³⁺ nanoparticles outperform AgGd(MoO₄)₂:Sm³⁺/Eu³⁺ nanoparticles as nanocatalysts. The AgGd(WO₄)₂:Sm³⁺/Eu³⁺ nanomaterial achieved an efficiency of approximately 94.8 % in degrading AMX under 90 min of UV light exposure, and demonstrated remarkable stability after five consecutive catalytic cycles. This work introduces a novel approach to simultaneous luminescent detection and photocatalytic degradation by utilizing Sm³⁺/Eu³⁺ co-doped AgGd(MoO₄)₂ and AgGd(WO₄)₂ nanomaterials, highlighting their unique potential for environmental monitoring and remediation. The combination of high sensitivity for MnO₄⁻ detection and superior photocatalytic degradation of antibiotics represents a significant advancement in multifunctional nanomaterials, providing a dual-function solution to address critical environmental contamination challenges.