Embodiments of the invention relate to producing hydrogen from a subsurface formation by injecting a reactant into the subsurface formation and reacting the reactant with the subsurface formation to form at least one of hydrogen gas or a mineralized product within the subsurface formation. The hydrogen produced is collected or one or more components of the reactant is sequestered to form a mineralized product in the subsurface formation. Other embodiments of the invention relate to producing hydrogen by injecting a thermal fluid into the subsurface rock formation, where the thermal fluid includes a reactant. The reactant is reacted with components in the subsurface formation to form at least one of hydrogen gas mineralized sulfur, or mineralized carbon.