Highly Stable MOF-76(Sm) Luminescence Sensor for Efficient Identification of D2O and H2O

Heavy water (D2O) is an essential solvent with extensive applications, notably as a neutron moderator in nuclear reactors, and plays a vital role in the fields of nuclear energy production and chemical analysis. Nevertheless, the strong interaction between H2O and D2O leads to the pronounced hygroscopic nature of D2O, and the significant similarities in their physical and chemical properties further complicate the distinction between these two substances. Consequently, it is imperative to develop a methodology for the detection of D2O content in H2O. In this work, we synthesized a water-stable MOF-76(Sm) luminescent sensor with lanthanide metal Sm and 1,3,5-benzenetricarboxylate anion. The Sm3+ ions in the MOF-76(Sm) can be effectively sensitized by the ligand and show a good luminescence response to the D2O–H2O system. Compared with the O–H bond of water, MOF-76(Sm) has a smaller vibration quenching of Sm3+ ions by the O–D bond of heavy water, which leads to the enhancement of the luminescence of D2O, and realizes the quantitative detection of D2O content in H2O. A series of experiments have demonstrated that this sensing material exhibits a robust fluorescence response across the entire range of the D2O–H2O system, enabling the quantitative detection of D2O in H2O. Furthermore, the material can be recycled and reused, underscoring its practical application value. The MOF-76(Sm) is expected to function as a precise, sensitive, and comprehensive quantitative instrument for evaluating the D2O content in water systems, all while ensuring its recyclability. This study offers empirical support for the advancement and utilization of the lanthanide element samarium, as well as for the broader application of current metal-organic framework (MOF) materials.