Mixed metal oxide nanocomposites derived from layered double hydroxides as photocatalysts for C.I. Basic Blue 3 degradation under UV light

In this research we report synthesis of the heterostructure Mg-Al-Zn mixed metal oxide (ZnO/MMO) nanocomposite photocatalysts derived from Zn(OH) ₂/Mg-Al-layered double hydroxides (ZLDHs) precursors. The obtained samples were characterized by the X-ray diffraction (XRD), FT-IR, BET surface area, ICP and TG/DTG methods. The chemical compositions and morphology of the synthesized materials were investigated by the energy dispersive X-ray analysis (EDX) and the transmission electron microscopy (TEM). The results reveal that at the reaction time 96 h, ZLDH has the highest crystalinity which was confirmed by the X-ray diffraction spectra. The calcined samples at 500, 600 and 700 °C for 4 h show that the crystallinity of the nanocomposite improves with the increase of calcination temperature. The photocatalytic activities of synthesized nanocomposites were compared for the degradation of C. I. Basic Blue 3 (BB3) dye under UV illumination in aqueous solution. Among the synthesized nanocomposites, ZnO/MMO calcined at 700 °C shows the highest efficiency towards the removal of dye. The effect of UV illumination on the stability of ZnO in ZnO/MMO nanocomposite and pure ZnO was also investigated. The results showed that the photostability of ZnO in ZnO/MMO nanocomposite is increased compared to the pure ZnO.