Hydrogen species within the metals: Role of molecular hydrogen ion H2+

► Novel mechanism of H2 interaction with outer and inner surface of transition metals. ► The inner surface concept is presented for the adsorption of permeable hydrogen species. ► Adsorbed hydrogen molecular ion H2+ as intermediate in H2 molecule dissociative ionization. ► Inner surface of metal phase is available only for H2+ and H+ ions. ► Hydrogen species within metals-ionic pair type hydrogen metallides H2+ · Me− and H+ · Me− adsorbed on the inner surface.