High efficiency Al-based multicomponent composites for low-temperature hydrogen production and its hydrolysis mechanism

In this study, a series of multicomponent Al-based composites were prepared by mechanical ball milling of Al powder, low-melting-point metals (Ga, In, Sn), NaCl, g-C3N4 and carbon nanospheres. The composites were thoroughly analyzed using state-of-art characterization techniques with respect to morphologies, structures, chemical compositions, thermal, and electrochemical properties, etc. The hydrogen production performance of Al-based composites has been investigated under three low-temperature conditions, including deionized water (275.15 K), snow-melting agent aqueous solution (253.15–273.15 K), and aqueous electrolyte solutions (KOH, FeCl3, CaCl2, ethylene glycol) at 233.15 K. The best hydrogen production performance with a hydrogen yield of 1133 mL·gAl−1 at 275.15 K and 1095 mL·gAl−1 at 253.15 K was obtained. Especially, no induction time was observed in either condition. Even at 233.15 K in KOH solution, its reaction induction time was around 6 s and final hydrogen yield reached 1057 mL·gAl−1. The observed hydrogen production capabilities of composites have been analyzed and understood in depth, and a tentative multicomponent activation mechanism for low-temperature hydrogen production was proposed as well.