Dynamic hydrogen generation phenomenon of aluminum fed liquid phase Ga–In alloy inside NaOH electrolyte

Abstract

Reaction between aluminum and water offers a simple way for hydrogen generation. However, the passive oxide film subsequently formed on Al would become a major obstacle for its continuous reaction. Gallium was proved to be an effective way to remove the passive oxide film through penetrating into Al granules, which fosters the reaction between Al and water. However, fabrications of Al–Ga alloy so far are generally highly time and energy consuming. Here, unlike the existing strategies of using solid state Al-rich alloys for the reaction system, the liquid phase alloy was introduced and prepared to develop an extremely simple source for hydrogen generation where the mass percentage of Al can be less than 1%. Such conceptual innovation would help maintain the alloy in liquid state which thus allows for rather convenient operation. To probe into the methodology, the dynamic hydrogen generation phenomenon of such Al-fed liquid phase GaIn alloy inside NaOH electrolyte was disclosed. According to the experimental observations, the hydrogen was generated mainly at the interface between the liquid metal and the Petri dish rather than the liquid metal-electrolyte interface. Homogenous hydrogen generation only takes place at the liquid–solid interface while heterogeneous hydrogen generation from the moving accumulated Al granules happens on all surfaces. The present finding is expected to open a new way towards low cost and straightforward hydrogen generation. It would also help better understand the mechanisms lying behind as well as the dynamic traveling behaviors of the aluminum powered gallium alloy machine.