A Luminescent Sensor for Trace Uranyl in Nature Water Systems Using a Terbium(III)-Organic Framework

Here, we have demonstrated a terbium(III)-organic framework ([Tb2(H2BTC)(BTC)(H2O)2]<middle dot>4H2O, denoted as 1) synthesized from 1,2,4,5-benzenetetracarboxylic acid (H4BTC) and TbCl3<middle dot>6H2O under hydrothermal conditions. Notably, 1 exhibits a highly efficient uranyl sensing capability in complex natural water systems such as lake water and seawater, featuring high sensitivity (K SV = 1.13 x 105 and 1.06 x 105 M-1, respectively), ultralow limit of detection (LOD = 17.47 and 18.62 nM, respectively) and excellent anti-interference ability. FTIR and XPS analyses revealed that uranyl ions coordinate with the free -COOH groups on the H2BTC2- ligand. Density functional theory (DFT) calculations unveiled that photoelectron transfer from H2BTC2- to UO2 2+ causes luminescence quenching of 1.