Dual-lanthanide hollow luminescence metal-organic frameworks and their sensing performance for trace water and nitrobenzene

Abstract

Dual-lanthanide hollow metal-organic frameworks, Tb1-x/Eux-MOFs (x = 0, 0.02, 0.04, 0.06, 1) were successfully synthesized by a one-pot solvothermal method. The tunable luminescence color of green-yellow-orange-red can be achieved by variation of the Tb3+/Eu3+ ratio. The energy transfer between Tb3+ and Eu3+ is confirmed by monitoring the excited states lifetime of 5D4 (Tb3+) and 5D0 (Eu3+), and can be regulated by water content, which indicates that organic ligand, 1,3,5-benzenetricarboxylic acid (H3BTC) has good antenna effect. Also, Tb0.98/Eu0.02-MOFs are used to be luminescence sensors for the detection of trace water and nitrobenzene (NB). By simultaneous monitoring of the emission intensity at 545 nm and 617 nm, the detection limits (LODs) for water are 0.0068% and 0.0081%, respectively. Those for NB are 0.0962 ppm and 0.0668 ppm, respectively. The sensing mechanisms (energy transfer for water and electron transfer for NB) are determined.