A luminescent metal-organic framework film fabricated on porous Al2O3 substrate for sensitive detecting ammonia

A novel metal-organic framework film MIL-124 film was prepared on porous α-Al 2 O 3 ceramic plate by in situ synthesizing. After introducing Eu 3+ ions to the free -COOH sites of the MIL-124 ligand channels, a luminescent MOF film MIL-124@Eu 3+ was obtained. Based on the chemical reaction between NH 3 and the -COOH, the formation of -COONH 4 which was demonstrated by FT-IR spectrum, affected the energy transfer between Eu 3+ ions and ligand, quenching the characteristic emission of MIL-124@Eu 3+ film. The limit of detection to ammonia was calculated as 26.2 ppm in ambient air. The XRD results demonstrated the long-term stability of this ammonia sensor. The excellent performance and economical synthesizing strategy of the MIL-124@Eu 3+ film exhibited potential application of this sensor for detecting ammonia gas.