Eu(II)-MOF as NIR probe for highly efficient instantaneous anodic electroluminescence realized environmental pollutant trace monitoring

One of the effective ways to prevent environmental pollutants from entering the human body and causing cancer is to detect them efficiently and sensitively in the external environment, even trace detection. Herein, we developed a rare Eu(II)-MOF (Eu(II)-Phen) as near infrared (NIR) probe to construct high instantaneous anodic electrochemiluminescence (ECL) sensor for trace detection of environmental pollutants. Eu(II)-Phen was synthesized by the reductant of glycine and the protectant of oleylamine, which avoided using a large amount of inert gas to prevent Eu2+ from oxidizing into Eu3+. The Eu(II)-Phen possessed high-efficiency ECL with the aid of tripropylamine (TPA) coreactant, which was certified by DFT, electrochemical and ECL characterization. Then, the double enhancement mechanism prompted the ECL efficiency to enhance: i) the high energy transfer efficiency brought from the antenna effect of ligand to Eu2+, ii) the faster and more generation of coreactant radical (TPA•) catalyzed by Fe3O4-Ag NRs. Moreover, under NIR emission, the constructed ECL sensor with Eu(II)-Phen can work stably in the harsh environment such as heavy pollution. Given its high instantaneous luminous efficiency, NIR emission, self-enhancement and designable merits, the constructed ECL sensor represents a promising practical platform for trace environmental monitoring to prevent pollutants from attacking the human body.