Dynamic measurements of hydrogen reaction with LaNi5−xSnx alloys

Abstract

Metal hydrides AB5Compression Purification a b s t r a c tThe study focuses on the reaction between hydrogen gas and LaNi 5Àx Sn x alloys, where 0 x 0.5, in broad temperature and pressure ranges. It was performed by means of dynamic volumetric techniques using specific equipment developed at our laboratory. IntroductionHydrides belonging to the so-called AB 5 family have been intensively studied during the last decades due to their potential for storing or purifying hydrogen. These alloys combine an extended range of equilibrium pressures with hydrogen and fast reaction kinetics at room temperature. Although their relatively low gravimetric capacity (around 1 wt.% H) in comparison with newly developed hydrogen storage materials hinders their use for mobile applications, they are still convenient for static applications. Among the AB 5 alloys, LaNi 5 has been the object of numerous studies due to its good hydrogen interaction properties at room temperature [1e3], its adequate resistance to cycling degradation[4e6] and to the possibility of recovering the material after degradation by means of a simple thermal treatment [4,7]. Several of LaNi 5 hydrogen interaction properties can be modified or adapted to a specific need by the partial substitution of its elements [8e10]. For example, it is possible to increase the equilibrium pressure by substituting part of La by Ce [11], or to achieve an improvement in electrochemical properties by replacing a fraction of La by Dy [12]. The partial substitution of Ni, on the other hand, has been reported to improve the resistance to thermal and pressure cycling degradation [3]. Ni substitutions also produce changes in the equilibrium pressure which could be useful for the development of applications based on these materials. In particular, it has been found that the substitution of small amounts of Ni by * Corresponding author. Centro Ató mico Bariloche, Av. Bustillo 9500, 8400 Bariloche, Argentina. Tel.: þ54 294 4445278; fax: þ54 294 4445299.E-mail address: baruj@cab.cnea.gov.ar (A. Baruj).Available online at www.sciencedirect.com journal h om epa ge: www.elsev ier.com/locate/he i n t e r n a t i o n a l j o u r n a l o f h y d r o g e n e n e r g y 3 8 ( 2 0 1 3 ) 7 3 3 5 e7 3 4 3

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