Enhanced photocatalytic degradation of lindane using metal–semiconductor Zn@ZnO and ZnO/Ag nanostructures

To achieve enhanced photocatalytic activity for the degradation of lindane, we prepared metal–semiconductor composite nanoparticles (NPs). Zn@ZnO core–shell (CS) nanocomposites, calcined ZnO, and Ag-doped ZnO (ZnO/Ag) nanostructures were prepared using pulsed laser ablation in liquid, calcination, and photodeposition methods, respectively, without using surfactants or catalysts. The as-prepared catalysts were characterized by using X-ray diffraction (XRD), field-emission scanning electron microscopy, high-resolution transmission electron microscopy, ultraviolet–visible (UV–vis) spectroscopy, and photoluminescence spectroscopy. In addition, elemental analysis was performed by energy dispersive X-ray spectroscopy. The obtained XRD and morphology results indicated good dispersion of Zn and Ag NPs on the surface of the ZnO nanostructures. Investigation of the photocatalytic degradation of lindane under UV–vis irradiation showed that Zn@ZnO CS nanocomposites exhibit higher photocatalytic activity than the other prepared samples. The maximum degradation rate of lindane was 99.5% in 40 min using Zn@ZnO CS nanocomposites. The radical trapping experiments verified that the hydroxyl radical (·OH) was the main reactive species for the degradation of lindane.