Hydrogen generation from hydrolysis of activated Al-Bi, Al-Sn powders prepared by gas atomization method Yuheng Liu, Xingjun Liu, Xinren Chen, Shuiyuan Yang, Cuiping Wang * College of Materials and Fujian Provincial Key Laboratory of Materials Genome, Xiamen University, Xiamen, 361005, PR China article info Article history: Received 9 December 2016 Received in revised form 20 February 2017 Accepted 28 February 2017 Available online xxx Keywords: Hydrogen generation Hydrolysis reaction Gas atomization Al-based powders abstract Highly activated Al-based composite powders with compositions of Al-20Bi and Al-20Sn (wt.%) were prepared by gas atomization method for hydrogen generation. The Al-20Bi powders formed incomplete coreeshell structure with Bi aggregating on the powder sur- face, while the Al-20Sn powders presented eutectic structure with Sn distributed homo- geneously on the grain boundaries of Al. The hydrolysis characteristics of these powders were investigated in distilled water. The results showed that the Al-20Bi and Al-20Sn powders exhibited high hydrolysis performance and violently reacted with distilled water at 30  C. Elevated temperature could significantly shorten the incubation time, as well as improve hydrogen generation rate and conversion yield of the powders. The hy- drolysis mechanism and oxidation resistance property of the powders were carefully investigated too. The miscibility gap and the large difference of linear thermal expansion coefficient between Al and Bi are responsible for the activation and high oxidation resis- tance of the Al-20Bi powders. © 2017 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved. Introduction Nowadays, the shortage of fossil fuel and arising environment pollution has caused a huge energy problem, and there is an urgent demand for renewable and green energy. In the past few decades, hydrogen has been widely recognized as the most promising alternative energy for its high calorific value, cleanliness and renewability [1e9], and studies concerning the generation of hydrogen have become prevalent [10e13]. To date, hydrogen generation via the hydrolysis of aluminum and its alloys has drawn a lot of interests because it is cheap, effective, environment-friendly and safe [14e17]. In practical applications, however, aluminum and its alloys are passive because of the formation of dense oxide layer on their surface [18e20]. Therefore, numerous efforts have been done on ruining the alumina oxide layer and, thereby, improving hydrogen generation efficiency of the hydrolysis reaction. In general, the strategies include reacting with the assistance of alkalis [21,22], oxide additives [23], graphite [24], amalgam [25], or other activators [26e30]. But these methods still suffer from the problems of high cost, low efficiency and environment hazards. Moreover, one widely used method is to fabricate aluminum alloys with low-melting-point metals (such as Mg, Zn, Li, Pb, Bi, Ga, In, Sn, etc.), which have been proved to be helpful to break the alumina oxide and improve the activity of * Corresponding author. Fax: þ86 592 2187966. E-mail address: wangcp@xmu.edu.cn (C. Wang). Available online at www.sciencedirect.com ScienceDirect journal homepage: www.elsevier.com/locate/he international journal of hydrogen energy xxx (2017) 1 e9 http://dx.doi.org/10.1016/j.ijhydene.2017.02.205 0360-3199/© 2017 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved. Please cite this article in press as: Liu Y, et al., Hydrogen generation from hydrolysis of activated Al-Bi, Al-Sn powders prepared by gas atomization method, International Journal of Hydrogen Energy (2017), http://dx.doi.org/10.1016/j.ijhydene.2017.02.205