Enhanced hydrogen generation from hydrolysis of MgLi doped with expanded graphite

Abstract

Hydrolysis of Mg-based materials is considered as a potential means of safe and convenient real-time control of H2 release, enabling efficient loading, discharge and utilization of hydrogen in portable electronic devices. At present work, the hydrogen generation properties of MgLi-graphite composites were evaluated for the first time. The MgLi-graphite composites with different doping amounts of expanded graphite (abbreviated as EG hereinafter) were synthesized through ball milling and the hydrogen behaviors of the composites were investigated in chloride solutions. Among the above doping systems, the 10 wt.% EG-doped MgLi exhibited the best hydrogen performance in MgCl2 solutions. In particular, the 22 h-milled MgLi-10 wt.% EG composites possessed both desirable hydrogen conversion and rapid reaction kinetics, delivering a hydrogen yield of 966 mL H2 g−1 within merely 2 min and a maximum hydrogen generation rate of 1147 mL H2 min−1 g−1, as opposed to the sluggish kinetics in the EG-free composites. Moreover, the EG-doped MgLi showed superior air-stable ability even under a 75 RH% ambient atmosphere. For example, the 22 h-milled MgLi-10 wt.% EG composites held a fuel conversion of 89% after air exposure for 72 h, rendering it an advantage for Mg-based materials to safely store and transfer in practical applications. The similar favorable hydrogen performance of MgLi-EG composites in (simulate) seawater may shed light on future development of hydrogen generation technologies.