Hydrogen production by auto-thermal reforming of ethanol over Ni catalyst supported on ZrO 2 prepared by a sol–gel method: Effect of H 2 O/P123 mass ratio in the preparation of ZrO 2 Min Hye Youn a , Jeong Gil Seo a , Ji Chul Jung a , Sunyoung Park a , Dong Ryul Park a , Sang-Bong Lee b , In Kyu Song a, * a School of Chemical and Biological Engineering, Institute of Chemical Processes, Seoul National University, Shinlim-dong, Kwanak-ku, Seoul 151-744, South Korea b Korea Research Institute of Chemical Technology, Daejeon 305-600, South Korea 1. Introduction Hydrogen is considered to be the most viable energy carrier in future due to its clean, renewable, and non-polluting nature [1–3]. Technological advances in hydrogen utilization like fuel cells make hydrogen more important as a next generation fuel [4,5]. Various hydrocarbon sources such as natural gas [6,7], gasoline [8], alcohols [9,10], and biomass [11] have been used for hydrogen production through catalytic reforming processes. In particular, ethanol has served as a promising source for hydrogen production, because it can be easily handled and is widely distributed around the world. In addition, ethanol has attracted much attention as an alternate hydrogen source due to its low toxicity and high volumetric energy density [12–14]. In hydrogen production by auto-thermal reforming of ethanol, nickel-based catalysts have been widely investigated due to their excellent C–C bond cleavage ability and low cost [15]. In general, the identity of support strongly affects the catalytic performance of supported nickel catalysts in the reforming reactions. Among various supporting materials, ZrO 2 is known to be very effective in inhibiting nickel sintering in the presence of water at high reaction temperature [16]. Zirconia also has high thermal stability and strong resistance against coke formation [17]. All these make zirconia well suited as a supporting material for nickel catalysts in the reforming reactions. It was previously reported that nickel catalyst supported on ZrO 2 showed better catalytic performance than that supported on ZnO, MgO, TiO 2 , and Al 2 O 3 in hydrogen production by auto-thermal reforming of ethanol, due to the favorable modification of electronic structure of nickel species on ZrO 2 [18]. In this work, zirconia (X-ZrO 2 ) supports were prepared by a sol– gel method using P123 as a crystal structure and physical property controlling agent with a variation of H 2 O/P123 mass ratio (X). 20 wt.% Ni catalysts supported on X-ZrO 2 (X = 2, 3, 4, and 5) were then prepared by an incipient wetness impregnation method for use in hydrogen production by auto-thermal reforming of ethanol. The effect of H 2 O/P123 mass ratio (X) on the catalytic property and catalytic performance of Ni/X-ZrO 2 (X = 2, 3, 4, and 5) catalysts was investigated. Catalysis Today 146 (2009) 57–62 ARTICLE INFO Article history: Available online 9 December 2008 Keywords: Hydrogen Auto-thermal reforming Ethanol Zirconia Nickel catalyst ABSTRACT Zirconia (X-ZrO 2 ) supports were prepared by a sol–gel method using P123 as a crystal structure and physical property controlling agent with a variation of H 2 O/P123 mass ratio (X). 20 wt.% Ni catalysts supported on X-ZrO 2 (X = 2, 3, 4, and 5) were then prepared by an incipient wetness impregnation method for use in hydrogen production by auto-thermal reforming of ethanol. The effect of H 2 O/P123 mass ratio (X) on the catalytic performance of Ni/X-ZrO 2 (X = 2, 3, 4, and 5) catalysts was investigated. Crystal structure and physical property of zirconia could be controlled by changing the H 2 O/P123 mass ratio during the preparation step. All the Ni/X-ZrO 2 (X = 2, 3, 4, and 5) catalysts exhibited complete conversion of ethanol at 500 8C, while product distributions over Ni/X-ZrO 2 (X = 2, 3, 4, and 5) catalysts were different depending on the H 2 O/P123 mass ratio. Hydrogen selectivity over Ni/X-ZrO 2 (X = 2, 3, 4, and 5) catalysts was monotonically increased with increasing reducibility of the catalyst and with increasing H 2 O/P123 mass ratio. Among the catalysts tested, Ni/5-ZrO 2 with pure tetragonal phase of zirconia showed the best catalytic performance in hydrogen production by auto-thermal reforming of ethanol. High surface area and small nickel crystalline size of Ni/5-ZrO 2 were also responsible for high catalytic performance of Ni/5- ZrO 2 catalyst. ß 2008 Elsevier B.V. All rights reserved. * Corresponding author. Tel.: +82 2 880 9227; fax: +82 2 889 7415. E-mail address: inksong@snu.ac.kr (I.K. Song). Contents lists available at ScienceDirect Catalysis Today journal homepage: www.elsevier.com/locate/cattod 0920-5861/$ – see front matter ß 2008 Elsevier B.V. All rights reserved. doi:10.1016/j.cattod.2008.10.028