Tuning Texture and Morphology of Mesoporous TiO2 by Non-Hydrolytic Sol-Gel Syntheses

Abstract

The development of powerful synthetic methodologies is paramount in the design of advanced nanostructured materials. Owing to its remarkable properties and low cost, nanostructured TiO2 is widely investigated for applications such as photocatalysis, energy conversion or energy storage. In this article we report the synthesis of mesoporous TiO2 by three different non-hydrolytic sol-gel routes, and we investigate the influence of the synthetic route and of the presence and nature of the solvent on the structure, texture and morphology of the materials. The first route is the well-known ether route, based on the reaction of TiCl4 with iPr2O. The second and third routes, which have not been previously described for the synthesis of mesoporous TiO2, involve the reaction of Ti(OiPr)4 with stoichiometric amounts of acetophenone and benzoic anhydride, respectively. All materials are characterized by XRD, N2 physisorption and SEM. By playing with the non-hydrolytic route used and the reaction conditions (presence of a solvent, nature of the solvent, calcination), it is possible to tune the morphology and texture of the TiO2. Depending on the reaction conditions, a large variety of mesoporous TiO2 nanostructures could be obtained, resulting from the spontaneous aggregation of TiO2 nanoparticles, either rounded nanoparticles, platelets or nanorods. These nanoparticle networks exhibited a specific surface area up to 250 m2 g−1 before calcination, or up to 110 m2 g−1 after calcination.

Tuning Polymer/TiO2 Nanocomposites Morphology by In Situ Non-Hydrolytic Sol-Gel Syntheses in Viscous Polymer Medium: Influence of the Polymer Nature and Oxygen Donor

“…Based on these previous results and the literature analysis [ 13 , 16 ], it appears interesting, complementary to the influence of the polymer nature, to study the impact of other oxygen donors on the nanofiller formation and resulting nanocomposite morphology. In particular, oxygen donors with aromatic groups should be suitable to promote interactions between TiO 2 fillers and polystyrene matrix.…”

“…A condensation degree value of 26% was obtained, slightly higher than the condensation degree of 20% determined for TiO 2 synthesized from acetic anhydride in the PS-Ti(O i Pr) 4 -Ac 2 O nanocomposite. Wang et al [ 16 ] also obtained a low condensation degree for the synthesis of TiO 2 fillers by the benzoic anhydride route in toluene. Indeed, a calcination yield of 53% was determined for this sample whereas the calcination yields for samples prepared by the ether and acetophenone routes were much higher (>90%).…”

“…Actually, as the reaction temperature was lower for fillers synthesized in ethanol, a lower condensation degree was reached which can explain the smallest fillers in this case. More recently, Wang et al [ 16 ] reported the synthesis of mesoporous TiO 2 by three different non-hydrolytic sol-gel (NHSG) routes: the common ether route between titanium chloride and diisopropyl ether with alkyl halide elimination and two original routes involving the use of titanium isopropoxide as titanium dioxide precursor and acetophenone or benzoic anhydride as oxygen donor. Syntheses were carried out in three different liquid media: without solvent (the oxygen donor acts as solvent), in toluene and in squalane.…”

Supported Cobalt Catalysts for Acceptorless Alcohol Dehydrogenation

“…The material possessed specific surface area of 117 m 2 g -1 , and is composed of 100% of TiO2 anatase. [52]…”

Sol-Gel Chemistry: From Molecule to Functional Materials

“…In addition to the silica-based hybrid materials, TiO 2 -based nanomaterials have been attracting tremendous interest due to their wide range of applications such as photocatalysis, catalysis, sensing, and energy conversion [32]. Mutin et al described the preparation of mesoporous TiO 2 , investigating how the texture and morphology could be tuned by changing the synthetic route or the nature of the solvent [33]. Three non-hydrolytic sol-gel routes based on the reaction of TiCl 4 with iPr 2 O and Ti(OiPr) 4 with stoichiometric amounts of acetophenone or benzoic anhydride were performed leading to TiO 2 rounded nanoparticles, platelets, or nanorods with different porosities.…”