Enhanced hydrogen production properties of a novel aluminum-based composite for instant on-site hydrogen supply at low temperature

Abstract

Al-water reaction for hydrogen production faces the problems of long induction time and low conversion efficiency at low temperature (below 273.15 K), which has seriously limited its applications. To realize the instant hydrogen production of Al composites at low temperature, low melting point metals (Ga, In, Sn) and additives (NaCl, g-C3N4, LiH) were selected to prepare Al composites with high reactivity. Compared with the other Al composites, Al alloy/NaCl/LiH/g-C3N4 composites exhibit the enhanced low temperature hydrogen production performance in 23 wt% NaCl aqueous solution at 253.15 K. For all Al alloy/NaCl/LiH/g-C3N4 composites, the induction time of Al-water reaction at 253.15 K has completely eliminated. The highest hydrogen generation volume of 1095 mL·gAl−1 and the maximum hydrogen generation rate of 120 mL·gAl−1·s−1 were obtained for Al alloy/NaCl/1.5%LiH/g-C3N4 composite. It is proposed that LiH can induce Al-water reaction instantly starting at 253.15 K. The released heat and micro alkaline environment further promote the Al-water reaction and enhance the hydrogen conversion efficiency. In particular, g-C3N4 additive can improve the antioxidant properties of Al composites. This study provides a novel way for the development and application of Al composites in real-time hydrogen production at low temperature.