Lanthanide Ce(III)/Tb(III) bimetallic coordination polymer as an advanced electrochemiluminescence emitter for epinephrine sensing application

Abstract

By rationally introducing Ce(III) and Tb(III) into a coordination polymer (CP), a series of lanthanide bimetallic coordination polymers (Tb:Ce-BCPs) has been prepared in this work. Compared with pure Tb-CP and Ce-CP, bimetallic Tb:Ce-BCPs show stronger and more stable ECL intensity, which is mainly attributed to the "dual sensitization effect" combined with the energy transfer from Ce(III) to Tb(III) and the antenna effect from the ligand to the center atoms of Ce(III) and Tb(III). In the meantime, after explore the ECL intensity and morphologies of all these Tb:Ce-BCPs, the results show that the morphologies and ECL intensities of Tb:Ce-BCPs can be adjusted by doping different molar ratios of Ce(III) in Tb:Ce-BCP. Excitingly, Ce(III) can also act as a co-reaction accelerator, effectively promoting S₂O₈^2- to generate more SO₄^•-, thereby enhancing the ECL intensity of Tb:Ce-BCP. That is to say, Ce(III) plays a triple role in Tb:Ce-BCP. Furthermore, the ECL strength of Tb:Ce-BCP decreased by only 1.8% and 3.5%, respectively after the modified electrode was scanned for 800 s and stored for one month. Enlightened by the excellent ECL properties of Tb:Ce-BCP, we modified Tb:Ce-BCP directly on the surface of electrode, and explored its application in electroanalytical chemistry through the detection of epinephrine (EP) and the detection limit is 33 fmol L^-1. Significantly, our ECL sensing strategy promotes the application of lanthanides in ECL sensor and opens vast possibilities for the synthesis of a new generation of ECL emitter in electroanalytical fields.

Keywords: Electrochemiluminescence; Emitter; Epinephrine; Lanthanide bimetallic coordination polymer.