UIO-66/Ag/TiO2 Nanocomposites as Highly Active SERS Substrates for Quantitative Detection of Hexavalent Chromium

Sensitive determination of Cr(VI) is great importance as this one the most toxic heavy metal ions in environment. In work, a metal–organic framework (MOF) material, UIO-66 (University Oslo, UIO), was introduced for first time to develop composite substrate, UIO-66/Ag/TiO2, sensitive SERS detection water. The composition, morphology, crystal structure and optical property UIO-66/Ag/TiO2 were characterized by SEM, XRD, EDX, UV-Vis Raman spectroscopy. control experiment revealed introduction TiO2 can improve adsorption Cr thus greatly enhance signal on substrate. also be tuned changing dosage TiO2. Under optimized conditions, used detect water with different concentrations, which showed high sensitivity good stability. signals linear increase concentration increases from 5 × 10−9 M 10−6 M. limit nM, lower than safe drinking standard US Environmental Protection Agency (1 μM). Detection range 1 10−7 real lake achieved. These results demonstrate potential composites substrates trace environmental field.