Rapid hydrogen generation through aluminum-water reaction in alkali solution

Abstract

The effects of CaO and waste lithium foil on the aluminum-water reaction are investigated in this study. When CaO and waste lithium foil are added to deionized water, the pH of the solution rises above 12 and the Al–H2O reaction is noticeably affected. Two rapid hydrogen generation processes and a passivation process are observed in CaO/Ca(OH)2 suspension. A slow reaction follows the rapid hydrogen generation in LiOH solution. At the beginning of the process, the rapid reaction in CaO/Ca(OH)2 suspension and LiOH solution corresponds the rapid consumption of OH– ions. A similar tendency as the hydrogen generation process in CaO/Ca(OH)2 is detected by the in–situ open circuit potential. Solutions of LiOH and CaO/Ca(OH)2 initially present a difference in the rate of hydrogen generation, but they demonstrate a similar behavior after the consecutive addition of Al batches. This may be due to the synergistic reaction of OH– ions and the self-catalytic behavior of Al(OH)3, formed as a by product of the reaction.