Smart Mn7+ Sensing via Quenching on Dual Fluorescence of Eu3+ Complex-Modified TiO2 Nanoparticles

In this work, titania (TiO2) nanoparticles modified by Eu(TTA)3Phen complexes (ETP) were prepared by a simple solvothermal method developing a fluorescence Mn7+pollutant sensing system. The characterization results indicate that the ETP cause structural deformation and redshifts of the UV-visible light absorptions of host TiO2nanoparticles. The ETP also reduce the crystallinity and crystallite size of TiO2nanoparticles. Compared with TiO2nanoparticles modified with Eu3+(TiO2-Eu3+), TiO2nanoparticles modified with ETP (TiO2-ETP) exhibit significantly stronger photoluminescence under the excitation of 394 nm. Under UV excitation, TiO2-ETP nanoparticles showed blue and red emission corresponding to TiO2and Eu3+. In addition, as the concentration of ETP in TiO2nanoparticles increases, the PL intensity at 612 nm also increases. When ETP-modified TiO2nanoparticles are added to an aqueous solution containing Mn7+, the fluorescence intensity of both TiO2and ETP decreases. The evolution of the fluorescence intensity ratio (I1/I2) of TiO2and ETP is linearly related to the concentration of Mn7+. The sensitivity of fluorescence intensity to Mn7+concentration enables the design of dual fluorescence ratio solid particle sensors. The method proposed here is simple, accurate, efficient, and not affected by the environmental conditions.