Mesoporous titania with anatase walls by flash induction calcination Karine Assaker a , Taissire Benamor b,1 , Laure Michelin b , Bénédicte Lebeau b,⇑ , Claire Marichal b , Marie-José Stébé a , Jean-Luc Blin a,⇑ a Université de Lorraine/CNRS, SRSMC, UMR 7565, F-54506 Vandoeuvre-lès-Nancy cedex, France b Université de Haute Alsace (UHA)/CNRS, Equipe Matériaux à Porosité Contrôlée (MPC), Institut de Science des Matériaux de Mulhouse (IS2M), UMR 7361, F-68093 Mulhouse cedex, France article info Article history: Received 12 June 2014 Received in revised form 4 September 2014 Accepted 9 September 2014 Available online 18 September 2014 Keywords: Ordered mesoporous TiO 2 Flash induction Mesoporosity release Crystallization Anatase abstract Induction heating has been used to thermally treat mesostructured TiO 2 with hexagonal 2D structure prepared by a combined Liquid Crystalline Template (LCT) and Evaporation Induced Self-Assembly (EISA) synthesis method. Induction treatment induces the decomposition of the structuring agent P123 and the formation of anatase. Highly ordered mesoporous titania with a semi crystalline framework can be obtained very fast, i.e. 5 min at 460 °C or 15 min at 300 °C. The recovered materials have similar struc- tural, textural properties and photoactivity towards the decomposition of methyl orange than the mes- ostructured TiO 2 obtained after ethanol extraction followed by a calcination at 400 °C in a conventional furnace. Ó 2014 Elsevier Inc. All rights reserved. 1. Introduction Titanium dioxide represents a good photocatalyst for waste- water treatment, air purification or self-cleaning surfaces and mesoporous titania with controlled porosity which usually allow to reach high surface area are of interest for these applications [1,2]. However, on the contrary of ordered mesoporous silica, their synthesis is much more difficult. Two mechanisms can lead to the formation of these ordered TiO 2 mesostructures [3–5]. The first one is the soft templating pathway which implies the co- assembly of the titania precursor and surfactant, similar to the preparation of ordered mesoporous silica. To release the poros- ity, the surfactant has to be removed and to do so. Different strategies have been developed such as calcination, solvent extraction, chemical oxidation, and supercritical fluid extraction, etc. [6–13]. However, the surfactant removal usually leads to the collapse of the mesostructure [14]. This collapse is mainly due to the phase transition from amorphous titania to anatase at about 250 °C and to rutile at 600 °C. The second way to prepare ordered mesostructures is the hard-templating method. In that case the mesoporous titania is prepared in a confined space, for example via replication of mesoporous silica. Since the tem- plate prevents collapse of the mesostructure upon calcination, the main advantage of this method is the preservation of the ordered mesopore channel array during the crystallization step at high temperature. Recently, a synthesis route based on Evap- oration Induced Self-Assembly (EISA) coupled with Liquid– Crystal Templated (LCT) methods was recently developed in Blin’s research group to produce ordered mesoporous titania with high surface area and good thermal stability [15]. Meso- structured titania were thermally treated from 150 °C to 550 °C under conventional calcination conditions (2 h under air in muf- fle furnace). Such calcination procedure is a long time process and thus energy consuming. Recently a flash calcination process using induction furnace was reported by Lebeau’s research group to remove the P123 Pluronic organic template from ordered SBA-15 type mesostructured silica [11]. The total P123 decompo- sition was achieved after 15 min of induction thermal treatment at 300 °C (or 5 min at higher temperatures). In the present paper we report the study of the thermal decomposition by induction of the P123 organic template occluded within porosity of meso- structured titania. In particular the structural and textural char- acteristics of mesostructured titania material were carefully investigated and compared to homologous materials heat treated under conventional conditions [15]. http://dx.doi.org/10.1016/j.micromeso.2014.09.028 1387-1811/Ó 2014 Elsevier Inc. All rights reserved. ⇑ Corresponding authors. E-mail addresses: benedicte.lebeau@uha.fr (B. Lebeau), jean- luc.blin@univ- lorraine.fr (J.-L. Blin). 1 Current address: Centre de Recherche et Technologie des Eaux (CERTE), Soliman 8020, Tunisia. Microporous and Mesoporous Materials 201 (2015) 43–49 Contents lists available at ScienceDirect Microporous and Mesoporous Materials journal homepage: www.elsevier.com/locate/micromeso