Improved hydrogen generation from Al/water reaction using different synthesized Al(OH)3 catalyst crystalline phases.

Summary: The catalytic influence of different crystalline phases of aluminum hydroxide nanoparticles for the hydrogen generation from the reaction of Al and water is described. In this study, different aluminum hydroxide powder crystalline phases (mixed‐phase, bayerite phase, gibbsite phase), (Al(OH)3), were distinctly prepared using precipitation methods in different solvents (methanol, ethanol, and HNO3) at room temperature (25°C). Interestingly, the materials synthesized using ethanol and HNO3 showed bayerite. Using methanol as the solvent showed a gibbsite phase confirmed by X‐ray diffraction, XPS, Raman spectroscopy, and field emission spectroscopy (FESEM). Hydrogen generation using small crystal sized bayerite phase and mixed‐phase show higher catalytic efficiency than the pure and large gibbsite phase powders and the catalytic effect of different crystalline Al(OH)3 catalysts in the order of mixed phase>bayerite phase>gibbsite phase. The bayerite phase catalyst displayed the highest yield (100%) within 2 hours, but the gibbsite phase showed around 60% to 70% yield for a long time of 15 hours. However, more gibbsite phase‐orientation would have strong catalytic power when it is small and plate‐like thin layer (S.No.4, mixed phases). ~100% yield of hydrogen can be produced from 1 g Al/100 g water system within ~40 minutes using 1 g synthesized Al(OH)3 (S.No.4). This work delivers a novel technique to generate hydrogen for movable devices. [ABSTRACT FROM AUTHOR]