Applied Catalysis B: Environmental 106 (2011) 609–615 Contents lists available at ScienceDirect Applied Catalysis B: Environmental jo ur n al homepage: www.elsevier.com/locate/apcatb Preparation and characterization of Pt/TiO 2 nanotubes catalyst for methanol electro-oxidation Bochra Abida a,∗ , Lotfi Chirchi a , Stève Baranton b , Teko Wilhelmin Napporn b , Hafedh Kochkar a , Jean-Michel Léger b , Abdelhamid Ghorbel a a Laboratoire de Chimie des Matériaux et Catalyse, Faculté des Sciences de Tunis, Campus Universitaire El-Manar 2092, El-Manar, Tunisia b Laboratoire de Catalyse en Chimie Organique, Equipe Electrocatalyse, UMR-CNRS 6503, Universite de Poitiers, 40 avenue du Recteur Pineau, 86022 Poitiers Cedex, France a r t i c l e i n f o Article history: Received 6 April 2011 Received in revised form 14 June 2011 Accepted 17 June 2011 Available online 24 June 2011 Keywords: Electrocatalysts Hydrothermal process Platinum nanoparticles Titanium dioxide nanotubes Methanol electro-oxidation a b s t r a c t Titanium dioxide nanotubes were prepared via a hydrothermal treatment of TiO 2 powder (Degussa P25). Obtained samples were analyzed by various techniques, such as transmission electron microscopy (TEM) and X-ray diffraction (XRD), which revealed that the crystal structure of the obtained materials was similar to that of H 2 Ti 2 O 5 ·H 2 O nanotubes, and were about 50 nm in length and 20 nm in diameter. Nitrogen adsorption–desorption isotherms indicated that synthesized solids are mesoporous materials with a multi-walled nanotubular structure and high specific surface area. The methanol oxidation reaction was investigated on platinum nanoparticles supported TiO 2 nanotubes (XC72). The electrocatalytic activity of the catalyst was measured by cyclic voltammetry. CO stripping voltammetry in acidic solutions was investigated to study the reaction of the catalysts towards poisoning by carbonyl compounds. The results demonstrated that Pt/TiO 2 nanotubes catalyst exhibits the best activity for methanol oxidation and were favorable for improving the tolerance to poisoning species. © 2011 Elsevier B.V. All rights reserved. 1. Introduction Direct methanol fuel cells have attracted considerable attention for their low weight, high power density, low operating tem- perature and low pollutant emission. In the near future, they represent an alternative power generation system especially for mobile and portable applications [1–5]. Platinum is a suitable elec- trocatalyst for the electro-oxidation of methanol. However pure platinum is a poor anode catalyst for methanol electro-oxidation at room temperature, because CO is generated as an interme- diate during methanol oxidation reaction and strongly adsorbed on platinum active sites [6–9]. The electrocatalytic activity of Pt nanoparticles for methanol reaction is dependent on various fac- tors including the size and dispersion of the particles, preparation methods, supporting materials, and their surface conditions. Gen- erally, a high dispersion of Pt based catalysts on a support is very critical for its electrocatalytic activity [10,11]. Recently, various works have been focused on Pt/transition metal oxide compos- ites systems, such as Pt/TiO 2 , Pt/SnO 2 , Pt/CeO 2 [12,13]. The metal oxide stabilizes Pt particles dispersion to favor the increase of active surface per unit weight of the catalyst. The aim of our studies is to investigate the effect of the substrate composition on the electrocatalytic activity of pure platinum nanoparticles. ∗ Corresponding author. Tel.: +216 71 88 34 24. E-mail address: abidabochra@yahoo.fr (B. Abida). Especially, titanium nanotubes prepared from TiO 2 (Degussa P25) powder by hydrothermal treatment are an attractive substrate for this study. This treatment was discovered by Kasuga et al. [14] treated TiO 2 in the 10 mol/L NaOH aqueous solution for 20 h at 383 K and nanotubes with 8 nm in diameter and 100 nm in length were obtained. This synthesis method was optimized by differ- ent studies by using different concentrations of NaOH aqueous solution as well using several raw materials and hydrothermal syn- thetic conditions [15]. Apart from the crystalline structure of TiO 2 anatase or a mixture of anatase and rutile some nanostructures of nanotubes were obtained with the formation of hydrogenoti- tanate H 2 Ti 2 O 5 ·H 2 O, H 2 Ti 3 O 7 , H 2 Ti 4 O 9 ·H 2 O [16]. Their tubular structure showed a larger surface area and a higher degree of porosity than TiO 2 powder, and an improvement of their photocat- alytic activity was evidenced [16]. In this work we are interested particularly to titanium nanotubes (H 2 Ti 2 O 5 ·H 2 O) [17,18], which present a high specific surface area compared with TiO 2 powders, caused by the nanotubular morphology [19]. They also exhibit a high ion-exchange capacity for cations of different metals [20], open mesoporous morphology [21], pronounced proton conduc- tivity and relatively good stability at elevated temperatures [22]. Furthermore, a strong interaction has been reported in the case of platinum catalysts dispersed on TiO 2 nanotubes leading to an improvement of the electrocatalytic activity of platinum when compared with platinum dispersed on other substrates. For ethanol oxidation, the results demonstrated that the titanium dioxide nanotubes can greatly enhance the catalytic activity of Pt and 0926-3373/$ – see front matter © 2011 Elsevier B.V. All rights reserved. doi:10.1016/j.apcatb.2011.06.022