ZnAl-LDH/MOF-5 heterostructure nanocomposite for photocatalytic degradation of organic dyes under sunlight irradiation

Layered double hydroxide based metal organic framework-5 (LDH/MOF-5) nanocomposite is synthesized by in situ nucleation and directed growth of MOF-5 crystals on LDH layers. The intercalated benzene dicarboxylate (BDC) ions of the LDH structures coordinate to the Zn2+ ions to form MOF-5 crystals, which are deposited on the surface of the LDH. The structural and morphological analyses of the LDH/MOF-5 nanocomposite are carried out by powder X-ray diffraction (PXRD) analysis, field emission scanning electron microscopy (FESEM), Fourier transform-infrared spectroscopy (FTIR), optical spectroscopy and thermo gravimetric analysis (TGA). Thus, the synthesized ZnAl-LDH/MOF-5 nanocomposite exhibits enhanced dye removal efficiency, compared to pure LDH and MOF-5. The nanocomposite is very selective towards the removal of anionic dyes. The methyl orange (MO) dye adsorption efficiency of ZnAl-LDH/MOF-5 is 51.41% and shows a plateau after 60 min of contact time. The ZnAl-LDH/MOF-5 nanocomposite exhibits an excellent dye removal efficiency of 99.98% after 40 min by a natural sunlight mediated photodegradation process. Such an efficient photocatalytic removal of toxic anionic dyes indicates the potential applications of the ZnAl-LDH/MOF-5 nanocomposite in industrial waste-water treatment.

Automated summary

The LDH/MOF-5 nanocomposite is synthesized by in situ nucleation and directed growth, and exhibits enhanced dye removal efficiency and selectivity towards anionic dyes. The nanocomposite shows excellent photocatalytic removal of toxic dyes, indicating its potential applications in industrial waste-water treatment.