Multifunctional Sm3+ doped LiAlSiO4 nanoparticles for efficient photocatalytic water treatment and high-frequency dielectric applications

Abstract

In this work, Sm³⁺ doped LiAlSiO₄ nanoparticles (1–11 mol%) are successfully synthesized via a solution combustion method and comprehensively characterized using X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDX), and Fourier-transform infrared (FTIR) spectroscopy. The optical bandgap was found to decrease systematically from 4.427 eV (undoped) to 4.074 eV for 11 mol% Sm³⁺ doping, indicating bandgap modulation through rare-earth incorporation. The dielectric behavior is investigated through measurements of complex permittivity (ε^⁎), dielectric loss (tan δ), and AC conductivity (σ) across varying frequencies and dopant concentrations. Results showed that both ε' and ε″, as well as tan δ, decreased with frequency, whereas σ exhibited an increasing trend. Notably, Sm³⁺ doping enhanced the conductivity compared to the undoped sample, confirming its potential for high-frequency dielectric applications. Photocatalytic activity is evaluated using Rhodamine B (Rh·B) as a model dye under UV light. The optimized LiAlSiO₄:11Sm³⁺ sample demonstrated exceptional photocatalytic efficiency, achieving 99.12 % degradation of Rh·B within 120 min. Further studies assessed the effects of catalyst loading 40 mg (73.4 %), dye concentration 5 pp. (99.23 %), pH 12 (99 %), and scavenger agents, revealing critical factors influencing degradation performance. The combined dielectric and photocatalytic properties highlight the multifunctionality of Sm³⁺ doped LiAlSiO₄ NPs for potential applications in environmental remediation and advanced optoelectronic devices.