TiO 2 Macroscopic Fibers Bearing Outstanding Photocatalytic Properties Obtained through an Integrative Chemistry-Based S
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TiO2 Macroscopic Fibers Bearing Outstanding Photocatalytic Properties Obtained through an Integrative Chemistry-Based Scale-Up Semi-Industrial Process
Natacha Kinadjian,1 Mickael le Bechec,2 Wilfrid Neri,1 Philippe Poulin,1 Sylvie Lacombe2 and Rénal Backov1 1
Centre de Recherche Paul Pascal, UPR 8641-CNRS, Université de Bordeaux, 115 Avenue Albert Schweitzer, 33600 Pessac, France. 2 IPREM-UMR CNRS 5254, Université de Pau et des Pays de l’Adour, Hélioparc-2 Av. du Président Angot, F-64053 Pau Cedex 09, France. ABSTRACT In here we depict the morphogenesis and associated properties of TiO2-based macroscopic fibers designed for the photodecomposition of volatile organic compounds (VOC). We employed a continuous industrially scalable extrusion-based process making the use of hybrid sols of amorphous titania nanoparticles, polyvinyl alcohol (PVA) and occasionally latex nanoparticles. This process allowed for the continuous generation of hybrid TiO2/latex/PVA or TiO2/PVA macroscopic fibers. Upon thermal treatment, biphasic porous fibers are obtained containing the anatase phase of TiO2 with 10-15% of brookite. These fibers, which can be manufactured under several hundred meter of length, are offering significantly improved phototocatalytic efficiency now comparable to the commercial Quartzel®PCO photocatalyst for gas-phase acetone mineralization. INTRODUCTION Photocatalysis is a multi-faceted chemical process dedicated to green chemistry and more generally to environmental science [1]. Particularly, the field of heterogeneous photocatalysis has expanded rapidly within the last four decades while the interdisciplinary nature of the field now encompasses the communities of semiconductors physics, surface sciences, photo- and physical chemistry, material science and chemical engineering [2] Titanium dioxide (TiO2), a typical n-type 3.2 eV band gap semiconductor, is mainly used as a photocatalyst due to its inertness to chemical environment, low cost and long-term photostability for pollutants photodecomposition in wastewater, drinking water and air [3]. The photocatalytic activity of TiO2 relies on several characteristics such as specific surface area, crystallinity, particles size [4]. It is mainly attributed to its anatase phase and it is known that higher crystallinity drastically enhances the photocatalytic activity of TiO2 materials [5]. TiO2 materials with both a large surface area and high crystallinity showed therefore enhanced activity for the degradation of pollutants [6]. For enhanced specific surface area, 2D-mesoporous TiO2 materials appear as excellent candidates [7]. Beyond crystallinity and mesostructure, TiO2 may be shaped under various morphologies including nanofibers, nanostructured films or coatings, which have also an influence on photocatalytic properties. More recently, works also focused on the fabrication of one-dimensional (1D) TiO2 photocatalysts, with a special attention paid to TiO2 nanotubes. The methods of choice for the fabrication of 1D TiO2 nanostructures, electrospinning offers several ad
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