Interactions among TiO2 and palygorskite revealed: Boost for stability of well-known photocatalyst

Anatase, is widely used in photocatalysis because it is environmentally friendly, low-cost and presents good catalytic activities. Nevertheless, the anatase nanoparticles tend to agglomerate resulting in degradation of catalysis efficiency. The agglomeration problem can be resolved, using the fibrous clay mineral palygorskite via TiO2 particles dispersion on its fibers. Hence, it should be possible the efficient photocatalytic activity to derive from the strong interactions among the initial compounds. Palygorskite-TiO2 nanocomposites were synthesized and characterized by X-ray diffraction, Fourier transform-infrared spectroscopy and transmission electron microscopy, while the exact interactions and possible spontaneous bonding between palygorskite and the anatase sphere were investigated by molecular simulations. Three different supercells of palygorskite were built, which were further interacted with the TiO2 sphere with suitable surfaces. The optimal TiO2 -palygorskite connection takes place among the Ti atoms of the curved TiO2 part with the O atoms from palygorskite's fibers surface via electrostatic interactions and the potential strong covalent bonds. The molecular simulations results are in good agreement with transmission electron microscopy data. Based on simulation we can see the curved part of anatase which interacts with the Ti atoms and is connected to the palygorskite fibers through several types of its surfaces via the O atoms. (C) 2021 Elsevier B.V. All rights reserved.