Hydrogen generation by the hydrolysis of mechanochemically activated aluminum-tin-indium composites in pure water

This paper presents results of our continuing project on the mechanochemical activation of Al-based composites for hydrogen generation [1,2]. A series of bi- and ternary Al, Sn, and/or In composites were mechanochemically prepared and their reactivities towards neutral pH water at ambient conditions determined. Hydrogen generation was compared to previously reported data from related studies in Refs. [1] and [2]. Scanning electron microscopy (SEM) energy dispersive x-ray spectrometer (EDS) analysis suggests that Sn and In could be distributed relatively homogeneously onto and into Al particles exteriors and interiors, respectively. Such distribution allowed continuous micro-galvanic activity between anodic Al and cathodic Sn and In during hydrolysis reactions. X-ray diffraction indicated that in-situ Sn–In intermetallic phase formation was determined by the Sn:In mol ratio of each composite. The formed Sn–In phases included Sn4In and SnIn3. Some AlSn phases were detected in ternary composites. Reactive composites (>95% yield) exhibited relatively similar reactivities and it was found that composites containing various intermetallic phases had shorter induction periods than composites containing a single intermetallic phase.