This study investigates hydrogen generation from the reaction of aluminum and water using aluminum hydroxide synthesized under different conditions as a catalyst. The catalysts were prepared using sodium aluminate, aluminum nitrate, aluminum chloride, graphite-assisted precipitation, and re-precipitation from inactive aluminum hydroxide. The effects of precursor salt, synthesis environment, and reactivation treatment on catalyst phase composition and hydrogen production efficiency were examined. Results indicate that sodium-aluminate-derived aluminum hydroxide produced the highest hydrogen generation efficiency, attributable to its distinct phase structure and surface properties.