“Naked” TiO2 capsulated in nanovoid microcapsule of poly(vinylidene fluoride) supporter with enhanced photocatalytic activity

In the field of photocatalytic dyes purification, the immobilization of TiO2 photocatalysts in polymeric supporters with high photocatalytic activity and mass transfer is still an important challenge. In this paper, pre-synthesized TiO2 (core)/oleic acid (OA) (shell) particles, denoted as TiO2/OA, was doped to poly(vinylidene fluoride) (PVdF) supporters and then irradiated under UV light to construct a novel complex, denoted as NTiP composites. Characterization of samples by FT-IR and SEM demonstrates NTiP composites are successfully fabricated. The average pore size and the BET surface area of NTiP composites obtained by BET method are, respectively. Additionally, the methyl orange adsorption and photocatalytic tests of NTiP composites present relatively outstanding results compared to TiO2 directly fixed to PVdF material, denoted as TiP composites, which demonstrate that the nanovoid layer between TiO2 particle and PVdF material left by UV irradiation could effectively liberate all the active sites of TiO2 particles and promote the mass transfer and photocatalytic activity. Therefore, NTiP composites as a novel TiO2-immobilized structure will have a promising application in the recovery of TiO2 catalyst with anti-decomposed polymeric material.

► Oleic acid (OA) is used to construct a core–shell structure of TiO2 doped to PVdF.
► TiO2 (core)/OA (shell) is doped to PVdF and then removed OA to make a novel complex.
► All active sites of TiO2 are liberated by the nanovoid layer between TiO2 and PVdF.
► The resulting nanovoid layer obviously improves the photocatalytic activity of TiO2.
► The process of TiO2 particles coated by OA layer is facile and easily controlled.