Achieving highly efficient hydrogen generation and uniform Ag nanoparticle preparation via hydrolysis of Mg9Ag alloy milled under hydrogen gas

• Mg9Ag alloy is employed for both hydrogen generation and Ag NPs preparation.
• Hydrogen yield reaches 730 mL g−1 within 25 min at 298 K for H2-milled Mg9Ag.
• Ag NPs with a size of less than 50 nm were obtained for H2-milled Mg9Ag.

A Mg9Ag alloy is employed as a medium for both production of hydrogen and preparation of Ag nanoparticles through hydrolysis. Mg9Ag milled under H2 exhibits very favorable structural characteristics, i.e., yielding a fine nanocrystal powder and partial hydrogen-induced phase decomposition. As a result, a hydrogen yield of 730 mL g−1 is obtained in 25 min at 298 K, a much higher rate than produced by samples not milled or milled under argon. Moreover, the hydrolysis by-product can be recycled to obtain Ag nanoparticles by removing insoluble Mg(OH)2 using an added HCl solution. These results show that this process provides a highly efficient method for economically produce hydrogen and Ag nanoparticles.