Spontaneous activation behavior of Ni 3 Sn, an intermetallic catalyst, for hydrogen production via methanol decomposition Meiqiang Fan a , Ya Xu a,* , Junya Sakurai a , Masahiko Demura a , Toshiyuki Hirano a , Yuden Teraoka b , Akitaka Yoshigoe b a Hydrogen Materials Unit, National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047, Japan b Quantum Beam Science Center, Japan Atomic Energy Agency, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5148, Japan article info Article history: Received 2 March 2015 Received in revised form 28 May 2015 Accepted 30 May 2015 Available online 18 August 2015 Keywords: Ni 3 Sn Intermetallic compounds and alloys Methanol decomposition Hydrogen production Catalytic activity Microstructure abstract The catalytic properties of single-phase Ni 3 Sn powder in the production of hydrogen via the decomposition of methanol were investigated in isothermal tests at 713, 793, and 873 K. The catalytic activity of Ni 3 Sn significantly increased with time at 793 and 873 K, but not at 713 K, suggesting that Ni 3 Sn is spontaneously activated at temperatures above 793 K. At these temperatures, Ni 3 Sn showed high selectivity for H 2 and CO production and low selectivity for CH 4 , CO 2 , and H 2 O production, indicating that methanol decomposition was the main reaction, and that side reactions such as methanation and wateregas shift re- action were suppressed. Surface analysis revealed that fine Ni 3 Sn particles were formed during the reaction, accompanied by a small amount of deposited carbon. The formation of these particles was suggested to be the cause for the spontaneous activation of Ni 3 Sn. Copyright © 2015, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved. Introduction In recent years, hydrogen production from methanol has attracted much research attention, as methanol has many qualities that are desirable for this reaction, such as its low cost and high H/C molar ratio [1,2]. Much effort has been made to develop an efficient, low-cost catalyst for hydrogen production from methanol. Ni-based catalysts have been widely studied for this reaction, and their catalytic perfor- mance has been significantly improved in the past 30 years [3e5]. However, a drawback of these catalysts is the formation of methane from the side reaction of the hydrogen and carbon monoxide, which decreases the efficiency of hydrogen pro- duction. Therefore, it is necessary to design Ni-based catalysts that suppress this methanation reaction. Abbreviations: BET, BrunauereEmmetteTeller; EDS, energy dispersive X-ray spectroscope; IMC, intermetallic compound; LHSV, liquid hourly space velocity; SEI, secondary electron image; SEM, scanning electron microscopy; TGA, thermogravimetric analysis; XPS, X-ray photoelectron spectroscopy. * Corresponding author. Tel.: þ81 298592573; fax: þ81 298592501. E-mail address: Xu.Ya@nims.go.jp (Y. Xu). Available online at www.sciencedirect.com ScienceDirect journal homepage: www.elsevier.com/locate/he international journal of hydrogen energy 40 (2015) 12663 e12673 http://dx.doi.org/10.1016/j.ijhydene.2015.05.197 0360-3199/Copyright © 2015, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.