Investigation on the Al/low‐melting‐point metals/salt composites for hydrogen generation

Abstract

A series of Al-Ga-In-Sn-NaCl composites were prepared by mechanical ball milling. NaCl contributes to the particle breakage and particle refinement during the ball milling process, but the hydrogen generation of the composites decreases as the content of NaCl exceeds 5%. Higher composite to water ratio led to reduction of the hydrogen generation for the Al-Ga-In-Sn-5% NaCl composite. In addition, compared to pure water, the hydrogen generation of this composite is lower in NaCl solution. These results indicate the higher ionic concentration in water is not conducive for hydrogen generation. During the hydrolysis process, the dissolution of NaCl in water increases the ionic concentration, so the excessive NaCl in the composite leads to the reduction of hydrogen generation. In addition, optimization of the milling time is important for hydrogen generation. By optimizing the milling time to 18 hours, hydrogen yield of the Al-Ga-In-Sn-5% NaCl composite reached 1150 mL g−1 at 25°C. Although the composites easily react with moisture in the air, the hydrogen yield of Al-Ga-In-Sn-5% NaCl and Al-Ga-In-Sn-10% NaCl composites can maintain 100% and 94% of the original after being exposed to the air for 5 and 10 days. Highlights A series of Al-Ga-In-Sn-NaCl composites were prepared by mechanical ball milling. NaCl contributes to the particle breakage and particle refinement during the ball milling process, but the hydrogen generation of the composites decreases as the content of NaCl exceeds 5%. By optimizing the milling time to 18 hours, hydrogen yield of the Al-Ga-In-Sn-5% NaCl composite reached 1150 mL g−1 at 25°C in pure water. The hydrogen yield of Al-Ga-In-Sn-5% NaCl and Al-Ga-In-Sn-10% NaCl composites can maintain 100% and 94% of the original after being exposed to the air for 5 and 10 days.