Core-shell structured iron nanoparticles for the generation of COx-free hydrogen via ammonia decomposition

The iron nanoparticles that are encapsulated by microporous and mesoporous silica shells were synthesized for the generation of COx-free hydrogen through the catalytic decomposition of ammonia. The encapsulated iron nanoparticles show excellent catalytic activity, giving 100% ammonia conversion in the 650-670 degrees C range. The core-shell structured catalysts are highly stable under the adopted reaction conditions owing to the stable silica shells that effectively prevent aggregation of iron nanoparticles. In contrast, the naked iron nanoparticles deactivated gradually at 670 degrees C and lost 18% ammonia conversion in a period of 63 h. (C) 2009 Elsevier B.V. All rights reserved.