Fig. 6.

Chemical sensing by MMMs containing NUS-24 nanosheets. a, b FE-SEM and EDX elemental mapping (carbon and nitrogen) images of the MMMs (scale bar, 50 μm in a and 5 μm in b). c Cross-sectional FE-SEM image of the MMMs (scale bar, 20 μm). d, e Optical (d) and fluorescence (e) photographs of the MMMs (scale bar, 5 mm in d. λ _ex = 365 nm). f AFM image of the MMMs. g Time-dependent fluorescence intensity changes (I/I ₀) of the MMMs upon 5 min exposure to VOCs vapors (λ _ex = 365 nm, λ _em = 530 nm). h The quenching percentages of the MMMs by VOC vapors after 1 and 5 min exposure. i Time-dependent fluorescence intensity changes (I/I ₀) of the MMMs upon 5 min exposure to metal ion solutions (λ _ex = 365 nm, λ _em = 530 nm). j The quenching percentages of the MMMs by metal ions after 1 and 5 min exposure. The error bars in h and j show standard deviations based on three independent measurements