Effect of copper on the electric conductivity of rhodium islet films and on the state of adsorbed hydrogen

Conductometric measurements have demonstrated that copper adatoms adsorbed on the surface of rhodium particles carry a positive charge. In the process of the adsorption of hydrogen at 397-533 K, it was found that the sign of polarization at the surface of Rh and RhCu islet films changes due to the partition of the hydrogen between the surface and bulk states. The effect of copper on the dissolution of hydrogen depends on the temperature of adsorption and the H 2 pressure. The activation energy of thermal desorption of H 2 from the rhodium islet film increases in the presence of copper from 50 to 108 kJ/mol, a behavior indicative of a strengthening of the H-Rh bond.