Fabrication of mesostructured Y₂O₃:Eu³⁺ materials from metal–organic frameworks and their H₂O₂-sensitive turn-off luminescence

Mesostructured Y₂O₃:Eu³⁺ phosphor particles were fabricated by a pyrolytic conversion from a pertinent metal–organic framework (MOF), namely, MOF-76(Y):Eu with 1,3,5-benzenetricarboxylic acid ligands, aiming at luminescence sensing of H₂O₂. Large rod-like MOF-76(Y):Eu particles 301 ± 150 μm in average length were initially obtained by a reaction at 80 °C for 24 h. They were converted to rod-like Y₂O₃:Eu³⁺ particles 122 ± 34 μm in average length after heating at 500 °C. The Y₂O₃:Eu³⁺ particles actually consisted of primary nanoparticles 7.55 ± 1.43 nm in average size and had a mesoporous structure with a high specific surface area of 80.8 m² g⁻¹. The photoluminescence intensity of the Y₂O₃:Eu³⁺ particles decreased after treating with an aqueous H₂O₂ solution, which was recognized as H₂O₂-responsive turn-off luminescence. Three other kinds of Y₂O₃:Eu³⁺ particles, including those obtained from other MOF particles synthesized at room temperature, were also prepared and the effects of the microstructure on the degree of turn-off luminescence were examined. It was then observed that the H₂O₂-sensitivity was enhanced more effectively by using the MOF-derived Y₂O₃:Eu³⁺ particles having the higher specific surface area.