MODIFICATION OF THE METHANATION ACTIVITY ON A NI(111) SURFACE BY AR ION-BOMBARDMENT

The influence of Ar+ sputtering and methanation at 500-degrees-C, 1 bar total pressure on the specific reaction rate was studied for a Ni(111) surface. It was found that the sputtering/reaction treatment increased the methanation activity by approximately 400%. By thermal desorption spectroscopy it was shown that a change in surface area is not responsible for the change in the activity. At the same time the high temperature feature of CO desorption from the Ar+ treated surface correlates well with the enhanced activity. Both can be explained by a structural changes of the Ni surface itself.