Effects of Cu additives on the hydrogen generation performance of Al-rich alloys

Cu-containing Al-Ga-InSn4 quinary alloys were prepared by a simple smelting method under a high-purity nitrogen atmosphere, and the alloys were cast at room temperature. The microstructures were investigated using X-ray diffraction (XRD) and scanning electron microscopy (SEM) with energy-dispersive X-ray (EDX) spectroscopy analysis. In addition to the InSn4 intermetallic compounds, elemental Cu was found in the alloys. As the Cu content increased, more holes and cracks were formed, and the Al(Ga) solid solution was pulverized. The melting points of Al compounds with the other elements were determined by differential scanning calorimetry (DSC). The alloy and water reactions were investigated at a water temperature of 40 °C. The Cu addition not only increased the hydrogen yield of the Al-Ga-InSn4 alloys but also stabilized the hydrogen generation from the Al-water reaction, which indicated that the Al-Ga-InSn4-Cu alloys are more suitable as fuel hydrogen sources for proton exchange membrane fuel cells. Based on the DSC and SEM with EDX studies, we propose the reasons for the changes in the Al-water reaction with the Cu addition.