Single atom surface diffusion of sulfur on Ni(111)

The surface diffusion of individual sulfur atoms on the Ni(111) plane has been investigated by field ion microscopy. The sulfur atoms were segregated to the surface by annealing the tip at 700 K. Surface diffusion on the (111) plane was detected at temperatures above 107 K with an activation energy of 0.29–0.30 eV. These results indicate a very high diffusion rate for sulfur on clean Ni(111) at typical reaction temperatures (e.g., 450–900 K for CO methanation).