Recombination of Hydrogen Atoms on Various Transition Metal Surfaces

A study has been made of surface recombination of hydrogen atoms on various transition metals. Hydrogen atoms were produced in the electric discharge tube by use of an alternating current. In order to prevent the reacting gas from reaching the undesired part of the sample, a method which may be called “an effusion method” was adopted here. The relative activity of two kinds of metal plates, stuck together by the solder or some such material, was determined, comparing the temperature rises of the sample by means of alternative exposure of each side surface to the reacting gas. The following results were obtained: a) Co>Fe>Ni>Ta>Mo>W>Ti>Cr>Mn>Cu b) Zr>Ti>Th c) Mo>U These orders of activity were examined from several points of view through the comparison of recombination activity with the work function, the d-character, the experimental heat of chemisorption, etc. The present results are still fragmentary but may suffice to show a qualitative trend.