Stability of skeletal nickel catalyst at elevated temperature

Summary

• 1. An investigation has been made of the thermal deactivation of a skeletal nickel catalyst in a current of nitrogen and in a vacuum.

• 2. It has been shown that a skeletal nickel catalyst is of good stability, to baking in a current of nitrogen in absence of organic substances. Its activity is not reduced by a two-hour baking at 300%; deactivation and dehydrogenation of the catalyst become appreciable only at 400° and higher, and they then become more and more marked as the temperature is raised.

• 3. When the catalyst is heated in a vacuum, its activity falls more rapidly than when treatment is carried out in a current of nitrogen.

• 4. The results obtained support our hypothesis that the most important cause of the loss in the activity of skeletal nickel catalyst under the usual conditions of hydrogenation is not recrystallization, but destruction of the active surface by chemical dehydrogenation and blocking.