Diffusion of Chemisorbed Hydrogen on a Nickel Catalyst

The diffusion of hydrogen atoms chemisorbed on a Raney‐nickel catalyst at 150°C was studied by measuring the intensity of quasielastically scattered neutrons. From the dependence of the peak form on the neutron momentum transfer, we deduce the surface diffusion constant D = (0.8 ± 0.2) · 10 −7 cm 2 /sec, the mean residence time of a proton at a chemisorption site ẗ = (2.7 ± 0.5) · 10 −9 sec and a mean proton jump distance between adsorption sites ρ = (3.0 ± 0.5) Å.