Thermodesorption of hydrogen from a tantalum foil

The effect of preliminarily treating the surface of a Ta foil in hydrogen and CO on the temperature dependence of the rate of hydrogen desorption in the range 573-783 K was studied. It was experimentally found that the largest amount of H2 was desorbed at the highest rate and highest desorption rate constant at 753 K. The activation energy of desorption was determined. The desorption process involves the transfer of hydrogen dissolved in the subsurface bulk Hsub to the surface: Hsub → Hs. The presence of Hsub caused a decrease in the Hs-Ta bond energy.