ABSORPTION OF HYDROGEN IN COPPER

Reduction of an alumina-supported copper catalyst under the conditions used as standard for the reduction of the Cu/ZnO/Al2O3 methanol-synthesis catalysts produces multilayers of hydrogen in the copper. This absorption of the hydrogen results in a reconstruction of the copper with the effect that only the surface hydrogen may be thermally desorbed. Thermal desorption of the surface hydrogen allows the surface copper atoms to migrate to a new structure, possibly their original structure, which prohibits thermally induced evolution of the subsurface hydrogen. Reduction of surface oxidised copper containing subsurface hydrogen by CO (0.1 bar, 473 K) results in the explosive evolution of subsurface hydrogen.