On-board hydrogen production by hydrolysis from designed Al–Cu alloys and the application of this technology to polymer electrolyte membrane fuel cells

Al–Cu alloys containing various amounts of Cu (2–5 wt.%) are designed to increase the hydrogen production rate in an alkaline solution by precipitating the electrochemically noble Al2Cu phase along the grain boundary. All of the Al–Cu alloys exhibit a microstructure with Al2Cu precipitates, which is electrochemically noble to Al in an alkaline solution, along the grain boundary. The hydrogen generation rate of Al–Cu alloys increases as the amount of Cu increases, and the Al- 5 wt.% Cu alloy exhibits a 4.7 times greater hydrogen generation rate than that of pure Al. This significant increase in hydrogen generation is affected by the combined action of galvanic corrosion and intergranular corrosion. When hydrogen produced by the hydrolysis of Al–Cu alloys is directly fed to a polymer electrolyte membrane fuel cell (PEMFC) anode, the cell voltage exhibits a stable value of approximately 0.73 V without a humidifier.

► Al–Cu (2–5 wt.%) alloys are designed for fast H2 generation from hydrolysis. ► Designed Al–Cu alloys have noble Al2Cu phase along the grain boundary. ► Al-5 wt.% Cu alloy exhibits about 5 times greater H2 production rate than pure Al. ► It is due to the combined action of galvanic corrosion and intergranular corrosion. ► When supplying H2 produced from this system to PEMFC, it is operated stably.