Biphasic Sol-Gel Synthesis of Microstructured/Nanostructured YVO₄:Eu³⁺ Materials and Their H₂O₂ Sensing Ability

Microstructured/nanostructured YVO₄:Eu³⁺ powders and films were synthesized through a biphasic sol-gel method, aiming at their application as H₂O₂ sensing materials based on the turn-off luminescence of Eu³⁺ ions. The synthesis was typically carried out at temperatures of 80 °C or lower by using organic solutions to dissolve vanadium alkoxide and aqueous solutions to dissolve yttrium and europium salts together with sodium carboxylates. The resultant crystalline YVO₄:Eu³⁺ powders and films were characterized as containing micrometer-sized particles comprising primary nanoparticles with high specific surface areas. A comparative study was performed on the H₂O₂-responsive turn-off luminescence properties for the above samples and those synthesized by a single-phase sol-gel or a conventional solid-state reaction method. The results indicated that the microstructural feature of the samples from the biphasic sol-gel method was effective for detecting H₂O₂ through its adsorption on the particle surface and quenching of the Eu³⁺ luminescence. The film samples showed repeatable and quantitative turn-off luminescence, thereby demonstrating their suitability as solid-state H₂O₂ sensors.