A method releases hydrogen by forming a second ionic liquid from a first ionic liquid by releasing hydrogen from the first ionic liquid by exposing the first ionic liquid to water and a catalyst. The first ionic liquid includes a cation and an anion including a borohydride. The release of the hydrogen forms a borate, which makes up the anion of the second ionic liquid. The cation of the first ionic liquid is the same as that of the second ionic liquid. A reaction system includes the first and second ionic liquids, water and a catalyst.