Irradiation effects of argon ion on a plate-type Raney nickel catalyst

The present paper deals with restoration of the catalytic activity of Raney nickel deactivated by heat treatment (1), electrochemical oxidation (2) slow oxidation in water by dissolved oxygen (3) and quick oxidation in air (4). The plate-type Raney nickel catalyst used in this experiment is convenient for this particular ion-bombarding technique. The fine powder catalyst usually used could not be applied to this technique. The catalysts deactivated by the methods (2, 3) were activated by means of radio frequency diode sputtering system. An ordinary nickel plate and Raney nickel catalyst heated at high temperature (method 1) or burned in air (method 4) could not be activated by argon ion bombardment, because of the strong Ni-Ni and Ni-O bonds. The appearance of activity in Raney nickel catalyst generally results from amorphous nickel structure, when aluminum is leached from Ni-Al alloy. Activity restoration of catalyst by argon ion bombardment is satisfactly explained on the basis of the same reason. (author)