N-GQDs and Eu3+ co-encapsulated anionic MOFs: two-dimensional luminescent platform for decoding benzene homologues

Abstract

Highly luminescent hybrids N-GQDs/Eu³⁺@Mg-MOF (N-GQDs = N atom doped graphene quantum dots and Mg-MOF = {[Mg₃(ndc)_2.5(HCO₂)₂(H₂O)][NH₂Me₂]·2H₂O·DMF}) have been synthesized and their photophysical properties were investigated. The resulting luminescent material can exhibit dual-emission from N-GQDs and Eu³⁺ when excited at 394 nm, whereas the emission of ligand-based and Eu³⁺ can be collected when excited at 349 nm. Exposed to a series of atmospheric benzene homologues (BTEX) in a sealed environment for 1 hour at 25 °C, N-GQDs/Eu³⁺@Mg-MOF shows excellent fingerprint correlations between the exact BTEX and the emission peak height ratio of I_L/I_Eu (luminescent intensity ratio of ligand-based emission at 414 nm and Eu³⁺-based emission at 618 nm) and I_Eu/I_N-GQDs (luminescent intensity ratio of l-emission based on N-GQDs at 443 nm and Eu³⁺-based emission at 618 nm), which makes it possible for this material to become a good platform for the detection of BTEX.