Ammonia Cracking Catalyzed by Ni Nanoparticles Confined in the Framework of CeO Support.

For the extraction of hydrogen from ammonia at low temperatures, we investigated Ni-based catalysts fabricated by the thermal decomposition of RNi intermetallics (R = Ce or Y). The interconnected microstructure formed via phase separation between the Ni catalyst and the resulting oxide support was observed to evolve via low-temperature thermal decomposition of RNi. The resulting Ni/CeO nanocomposite exhibited superior catalytic activity of ∼25% at 400 °C for NH cracking. The high catalytic activity was attributed to the interlocking of Ni nanoparticles with the CeO framework. The growth of Ni nanoparticles was prevented by this interconnected microstructure, in which the Ni nanoparticles incorporated nitrogen owing to the size effect, whereas Ni does not commonly form nitrides. To the best of our knowledge, this is a unique example of a microstructure that enhances catalytic NH cracking.