TiO₂/ZnLDH as a Self-Assembled Nanocomposite with Photoresponsive Properties

A novel bicomponent photoresponsive nanocomposite consisting of zinc-based anionic clay (ZnLDH)-supported anatase TiO 2 nanoparticles was obtained by the structural reconstruction of the zinc-containing clay in a TiOSO 4 aqueous solution and was characterized by X-ray diffraction, IR spectroscopy, transmission electron microscopy, energy-dispersive X-ray spectroscopy, field emission scanning electron microscopy, X-ray photoelectron spectroscopy, and N 2 adsorption at 77 K. The reconstruction process of the Zn-based clay in a TiOSO 4 aqueous medium at room temperature produced significant effects on the structure, texture, surface, and morphology features as opposed to the parent ZnLDH, giving rise to a complex nanoarchitecture consisting of nanoparticles of TiO 2 (average size = 7 nm) deposited on the larger nanoparticles (∼100 nm) of the zinc-substituted anionic clay. The photoresponsive properties of TiO 2 /ZnLDH were analyzed by the evaluation of the optical characteristics and the catalytic behavior in the process of phenol photodegradation. The photocatalytic performances might arise from the specific nanotexture of the obtained titania−zinc-based nanocomposite self-assembly that can enhance the light harvesting and the ability of generating photoinduced electron−hole pairs of the active sites and the favorable electron-transfer properties of the heterojunctions of the TiO 2 /ZnLDH semiconductor.