Fig. 1. Effects of polyphenols on the physicochemical properties of MOF nanoparticles and the synthesis mechanism of hollow MOFs.

a–c SEM images of ZIF-8 nanoparticles at different reaction times, a 0 min, b 2 min, and c 5 min. The inset picture is the corresponding TEM image (scale bars, 100 nm); d, e N₂ adsorption-desorption isotherms of ZIF-8 (d) and HZIF-8 (e); f XRD patterns of ZIF-8 and HZIF-8; g FT-IR spectra of TA, ZIF-8, and HZIF-8; h Zeta potential of ZIF-8 and HZIF-8 in deionized water (the inset image shows the particles dispersed in water and left to stand for 1 h). Error bars represent the standard deviation of three independent measurements; i Schematic illustration of the synthetic process and mechanism for TA-tailored HZIF-8. The 2-MI represents 2-methylimidazole, the blue ball represents nitrogen atom, the gray ball represents carbon atom, and the white ball represents hydrogen atom.