Preparation and characterization of hydro-reactive Mg-Al mechanical alloy materials for hydrogen production in seawater

► Hydro-reactive Mg-Al mechanical alloy materials were prepared by high-energy milling. ► Hydrolysis properties and mechanism of Mg-Al alloy materials were studied in seawater. ► High-energy ball milling is an efficient method for improving the reactivity of Mg-Al alloy materials in seawater. ► Bi and Co as the cathode plays an important role in the hydrolysis of Mg-Al alloy in seawater.