Ag-Coated Heterostructures of ZnO-TiO2/Delaminated Montmorillonite as Solar Photocatalysts

Abstract

Heterostructures based on ZnO-TiO2/delaminated montmorillonite coated with Ag have been prepared by sol–gel and photoreduction procedures, varying the Ag and ZnO contents. They have been thoroughly characterized by XRD, WDXRF, UV–Vis, and XPS spectroscopies, and N2 adsorption, SEM, and TEM. In all cases, the montmorillonite was effectively delaminated with the formation of TiO2 anatase particles anchored on the clay layer’s surface, yielding porous materials with high surface areas. The structural and textural properties of the heterostructures synthesized were unaffected by the ZnO incorporated. The photoreduction led to solids with Ag nanoparticles decorating the surface. These materials were tested as photocatalysts for the degradation of several emerging contaminants with different nitrogen-bearing chemical structures under solar light. The catalysts yielded high rates of disappearance of the starting pollutants and showed quite stable performance upon successive applications.

Synthesis of the ZnTiO3/TiO2 Nanocomposite Supported in Ecuadorian Clays for the Adsorption and Photocatalytic Removal of Methylene Blue Dye

“…It is known that the separation, recovery, and reuse of the photocatalyst particles are important issues determining the future application of photocatalytic technology [ 72 ]. Therefore, in the present work, extrudates of photocatalyst-clay were prepared to facilitate the recovery of the synthesized composites.…”

Characterization and Effect of Ag(0) vs. Ag(I) Species and Their Localized Plasmon Resonance on Photochemically Inactive TiO2

“…In addition, the BE of Ag 3d3/2 is located at 373.32 eV. Those two peaks indicate the formation of Ag I species [51]. The peak is asymmetric and broad and therefore it is designated to two Ag species (Ag I and metallic Ag).…”

Photoactive nanoarchitectures based on clays incorporating TiO2and ZnO nanoparticles

“…Also, TiO 2 –ZnO@clay nanoarchitectures derived from a smectite (Cloisite ® 30B) have been also prepared by sol–gel reactions involving the delamination of the silicate. The resulting materials show good photocatalytic activity for the photodegradation of pollutants such as the pharmaceutical drugs acetaminophen and antipyrine and the pesticide atrazine [147,159,162]. TiO 2 –ZnO@clay materials have been also prepared from fibrous clay minerals such as sepiolite, as recently reported by Vaizoğullar [160].…”