Ni-Induced Novel Multi-Al-Alloys for Efficient and On-Demand Hydrolysis-Based Hydrogen Generation

Hydrogen generation via aluminum-water reactions offers a safe, on-demand, and sustainable pathway to a clean energy solution for global energy and environmental challenges. However, the formation of passive oxide layers disrupts the reaction kinetics in hydrolysis. In this study, novel quaternary Al-Zn-Si-Ni alloys containing 0.1 and 0.5 wt % Ni were developed to enhance hydrogen generation via hydrolysis in alkaline media. Structural, surface, and electrochemical analyses revealed that Ni addition promotes the formation of Al-Si-Ni and Al-Ni secondary phases, modifies the microstructure morphology, accelerates anodic dissolution, and increases electrochemical activity. The hydrogen generation rate increased 2.3 times for 0.5% Ni content with respect to the Ni-free alloy. The apparent activation energy decreased from 81.91 to 17.28 kJmol^-1, indicating accelerated reaction kinetics. Electrochemical measurements confirmed lower charge-transfer resistance and decreasing passivation with increasing Ni content and agree with the hydrogen generation results. FESEM image analysis showed that with increasing Ni content, the secondary particle surface phase ratio increased from 0.38% to 1.65%, and the average particle area increased from 5.24 μm² to 13.14 μm². This increased the galvanic activation, thereby increasing the hydrogen generation rate. Overall, Ni doping effectively activates Al alloys by altering their microstructure and electrochemical behavior, enabling a rapid and efficient hydrogen production. These findings provide practical guidance for manufacturing multicomponent aluminum alloys for on-demand hydrolysis-based hydrogen applications.