Poisoning of the platinum-catalyzed oxidation and hydrogenation of graphite by addition of CCl₄

The effect of chlorine addition upon the oxygen and hydrogen gasification of graphite has been examined using controlled atmosphere electron microscopy. When chlorine is added to the oxygen feed in the form of carbon tetrachloride the channeling of platinum catalyst particles ceases; when the poison is removed from the feed, the catalyst resumes channeling at a reduced rate. When the chlorine is added to the hydrogen feed channeling also ceases. However in this case simply removing the poison from the feed does not restore activity. An intermittant oxygen treatment of the deactivated specimen is effective in restoring catalytic channeling.