Preparation and catalytic properties of cerium hydride

Cerium hydride was formed at a moderate temperature (523 K) and atmospheric pressure using a pulse-flow technique. Its adsorption and catalytic properties were probed using deuterium, oxygen, carbon monoxide, carbon dioxide, methanol, and propyne. Deuterium exchange with the hydrogen of the hydride was examined and not all of the hydrogen was found to be exchangeable. It is likely that this was due to the nature of the pulse reaction where the residence time was too short to allow diffusion of hydrogen through from the bulk material. The hydride did not adsorb or react with either carbon monoxide or carbon dioxide. In contrast there was extensive reaction with oxygen resulting in water formation and a significant rise in temperature. The interaction between the hydride and methanol gave rise to adsorption and, at low levels, methane and hydrogen. This unusual reaction was facilitated by the formation of cerium oxide. Propyne hydrogenation was also shown to occur over cerium hydride but a hydrogen source other than the hydride was required.