Colloidal down-shifting Gd2O3:Eu3+/SiO2 phosphors nanocomposites using one-pot modified surfactants-based soft templates for catalytic applications

Abstract

The application of rare earth (RE)-based phosphor materials faces a significant challenge in adopting strategies to bring down the cost without compromising their properties. The most straightforward approach is to minimize the use of RE elements. Herein, we demonstrate the use of SiO₂ as an economical solid nano-matrix for lanthanides-based phosphor nanomaterials. Gd₂O₃:Eu³⁺(x%) and Gd₂O₃:Eu³⁺(x%)/SiO₂ nanophosphor composites were prepared through a modified soft templating technique using cetyltrimethylammonium bromide (CTAB) as the surfactant. The photoluminescence properties were studied by excitation, emission, and luminescence decay investigations. Upon excitation in the O²⁻(2p)→Eu³⁺(4f⁶) LMCT state, these nanophosphors exhibited predominantly red emission from the ⁵D₀→⁷F_J transition (where J = 0–4) of the Eu³⁺ ion. Moreover, the synthesized low-cost Gd₂O₃Eu³⁺(5 %)/SiO₂ composites, with a small number of lanthanides, exhibited excellent photocatalytic degradation activity for organic dye (methylene blue) under visible light (λ ≥ 420 nm), showing promising potential for photocatalytic wastewater treatment.