Lewis bases are chemical compounds, or molecules, that can donate a pair of electrons to Lewis acids, compounds, or molecules with two free slots in their highest occupied molecular orbital. Water can act as either a base or an acid depending on the other substances available for chemical interactions. In the case of the aluminum, the water acts as a Lewis base, interacting with the Lewis acids in the aluminum cluster, and as a Lewis acid interacting with the Lewis bases in the aluminum cluster. The oxygen in the water binds to the Lewis acid aluminum while the Lewis base aluminum frees a hydrogen atom. If more than one hydrogen atom is freed, they bond with each other in pairs to create hydrogen gas and break off from the aluminum cluster.
Researchers plan to examine ways this process can be used to break the bonds of other molecules and also to explore ways to reuse the aluminum clusters over and over again for hydrogen production. This involves breaking the bond between the oxygen atoms and the aluminum Lewis acid sites, thus removing the hydroxyl groups remaining attached to the aluminum clusters after hydrogen is produced.