posted on 2023-10-18, 22:16authored byHiroshi Mizoguchi, Yuta Osawa, Masato Sasase, Naoki Ohashi, Masaaki Kitano, Hideo Hosono
For the extraction of hydrogen from ammonia at low temperatures,
we investigated Ni-based catalysts fabricated by the thermal decomposition
of RNi5 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 RNi5. The resulting Ni/CeO2 nanocomposite exhibited superior catalytic activity of ∼25%
at 400 °C for NH3 cracking. The high catalytic activity
was attributed to the interlocking of Ni nanoparticles with the CeO2 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 NH3 cracking.