Please cite this article in press as: R. Palacio, et al., Appl. Catal. A: Gen. (2015), http://dx.doi.org/10.1016/j.apcata.2015.03.041 ARTICLE IN PRESS G Model APCATA-15331; No. of Pages 12 Applied Catalysis A: General xxx (2015) xxx–xxx Contents lists available at ScienceDirect Applied Catalysis A: General jou rn al hom ep age: www.elsevier.com/locate/apcata Decomposition of ethanol into H 2 -rich gas and carbon nanotubes over Ni, Co and Fe supported on SBA-15 and Aerosil Ruben Palacio a , Jaime Gallego a,b , Zelimir Gabelica c , Catherine Batiot-Dupeyrat a , Joël Barrault a , Sabine Valange a,∗ a Université de Poitiers, Institut de Chimie des Milieux et Matériaux de Poitiers (IC2MP), UMR CNRS 7285, ENSIP, B1, 1 rue Marcel Doré, TSA 41105, F-86073 Poitiers Cedex 9, France b Química de Recursos Energéticos y Medio Ambiente, Instituto de Química, Facultad de Ciencias Exactas y Naturales, Universidad de Antioquia UdeA, Calle 70 No. 52-21, Medellín, Colombia c Université de Haute Alsace, ENSCMu, Laboratoire GSEC, 3, Rue A. Werner, F-68094 Mulhouse Cedex, France a r t i c l e i n f o Article history: Received 26 January 2015 Received in revised form 25 March 2015 Accepted 26 March 2015 Available online xxx Dedicated to Prof Jacques Vedrine. Keywords: Ni, Co, Fe supported on silica SBA-15 Ethanol decomposition Hydrogen production Carbon nanotubes a b s t r a c t SBA-15 with a 2D hexagonal mesoporous structure exhibiting a narrow pore size distribution and com- mercial AEROSIL380 silica were used as supports for the dispersion of Ni, Co or Fe metal oxide particles. After reduction at 973 K, catalytic properties of these materials were evaluated for ethanol conversion to H 2 and carbon nanotubes (CNTs). The reduced composites were selective for hydrogen production as follows: iron (45–55%) < cobalt (55–70%) < nickel (70–80%) regardless of the type of silica used as support. The nickel-based catalysts appeared to be the most active for the production of hydrogen and also gen- erate carbon nanotubes in large amounts, independently of the support porosity. HRTEM micrographs showed a generally well-defined morphology and a quite uniform outer diameter of CNTs produced using the Ni composites. The texture of the silica support had however a particular influence on the catalytic properties of the cobalt-based catalysts. Both Ni and Co supported on SBA-15 silica generate a mixture of CNTs and carbon nanofibers (CNFs) with a wider size distribution compared with that of the CNTs produced over Ni/Aerosil. This lack of selectivity was attributed to the expelling of Co particles from the SBA-15 mesoporous channels upon reduction. All Fe/silica materials proved the least active and selec- tive. Along the major carbon fibers, they generate a few poorly defined multi-walled CNTs with small diameter. TG analysis indicated that all CNTs exhibit a relative high stability in an oxidizing atmosphere. © 2015 Elsevier B.V. All rights reserved. 1. Introduction The energy consumption increases all over the world so that new environmentally friendly but efficient energy sources must be found. Hydrogen, as a strategic fuel, was largely studied on account of its various important applications [1–3]. Besides the well-known processes using natural gas as hydrogen source, it can also be pro- duced by water electrolysis, gasification and partial oxidation of heavy oil or hydrocarbon steam reforming reactions [4]. Among these classical hydrogen production methods its generation by the reaction of a metal, metal alloy or of metallic salts/compounds with water was recently shown being a real-time system able to supply hydrogen for mobility and transport [5]. Ethanol was also tested as raw material for hydrogen production because of its low ∗ Corresponding author. Tel.: +33 5 49454048. E-mail address: sabine.valange@univ-poitiers.fr (S. Valange). cost, wide production, easy generation from renewable sources, low toxicity and relatively high hydrogen content [6]. Recently an important attention was paid to the simultaneous production of hydrogen and carbon nanotubes by using Fe/La 2 O 3 or Ni/La 2 O 3 as catalysts obtained upon reduction of LaFeO 3 or LaNiO 3 perov- skite type structures [7,8]. Currently mass production of CNTs is achieved by the conventional CVD method by using a wide number of carbon sources such as methane, ethylene, acetylene and ethanol [9]. Single- and multi-walled CNTs and carbon nanofibers (CNFs) were successfully prepared by CVD using ethanol as carbon source, converted on various catalysts [10]. Single- and multi-walled car- bon nanotubes (respectively SWCNTs and MWCNTs), as well as CNFs were also formed when using transition metal particles sup- ported on alumina as catalysts [2,3,11]. After describing the ethanol decomposition mechanisms over Fe/Al 2 O 3 [2] and Ni/Al 2 O 3 [3] at different temperatures, Wang and coworkers [12] have evaluated thermodynamic parameters characterizing the various reactions leading to H 2 , CO, CH 4 and CNTs. The same group confirmed the http://dx.doi.org/10.1016/j.apcata.2015.03.041 0926-860X/© 2015 Elsevier B.V. All rights reserved.