Hydrogen generation by hydrolysis reaction using magnesium alloys with long period stacking ordered structure

Abstract In the present work are reported the hydrogen generation performances of Long Period Stacking Ordered (LPSO) compounds with 18R, 14H and 10H-type structures by hydrolysis reaction in simulated seawater solution (35 g/L NaCl). LPSO compounds and LPSO + Mg alloys synthesized by induction melting are described in the light of their microstructural and electrochemical properties. Except for 10H type, all LPSO present improved H2 generation features compared to pure Mg. Indeed, 80% of the reaction is achieved in less than 40 minutes. The highest generation yield of 90% is obtained for single phase LPSO Mg87.6Ni5.5Y6.9. Alloys containing both Mg and LPSO beneficiate from galvanic coupling between the two phases leading to higher reactivity. The activation energies of 27.3 and 85.4 kJ/mol determined for Mg91Ni4Y5 (14H + Mg) and Mg83.3Cu7.2Y9.5 (18R) respectively clearly highlight this benefit from galvanic coupling.