The present invention combines the storage capacity of redox flow batteries and the prodn. of H and other products of chem. redox reactions. The redox couple of each electrolyte is chem. regenerated on a specific catalyst bed, replacing the discharging processes of the battery, while oxidizing or reducing other species present. This allows for the prodn. of H on the cathodic side, and various useful products on the anodic side, such as O for fuel cell application. The proposed system uses a dual circuit arrangement from which electrolytes may be pumped through the catalyst beds as desired, once they are in their charged state. [on SciFinder(R)]