Morphology and composition of Al-Si-Mg alloys regulated hydrogen generation

In-situ hydrogen generation from Al-based alloys has been considered for providing safe and convenient hydrogen for fuel cells. However, the hydrogen generation from Al-Si-Mg alloys, which are widely used in industry, and the corrosion of different compositions in alkaline solution are rarely discussed. Herein, hydrogen generation from spherical Al-Si-Mg alloys with different components is studied. The results show that these alloys are composed of multiphases, which affect their surface morphology and hydrogen generation rate. Surface with many cracks provide active sites that favor OH- permeation and hydrogen evolution. The evaluated temperature, whether from the working ambient or interface, obviously accelerates Al corrosion. During the continuous addition of these alloys, a dormant period appears for AlSi10Mg0.25-0.45 due to the rapid consumption of OHions. Moreover, the current produced is related to the hydrogen generation rate, with varying hydrogen generation rates reflecting differences in reducing ability. The corrosion stars from the pitting and extends along the Al matrix, leading to the formation of a porous byproduct. This study provides a concept for designing the materials for the improved conversion of hydrogen to electricity.