Low temperature decomposition of hydrous hydrazine over FeNi/Cu nanoparticles

A simple, surfactant-free liquid-phase reduction of Cu, Ni and Fe salts (e.g. nitrates, chlorides) was used to prepare nanostructured FeNi/Cu catalysts for hydrous hydrazine (N-2 H-4 center dot H2O) decomposition. The synthesis of nanomaterials includes reduction of copper salt using N2H4, followed by rapid reduction of iron and nickel salts by NaBH4. The catalysts were characterized by XRD, BET, TEM, XPS, XANES/EXAFS techniques and their activity and selectivity was studied during hydrous hydrazine decomposition at temperatures ranging from 300 to 345 K. The selectivity to hydrogen increases to similar to 100% with increasing temperature up to similar to 345 K. The catalytic performance of these materials depends on the structure of NiFe layer formed over a Cu core, which may be controlled by changing of NiFe/Cu mass ratio. Investigation of the catalytic performance for bi- and tri-metallic materials show that main active metal is nickel but a NiFe alloy could be responsible for the increased selectivity. Alloying of nickel with iron coupled with a favorable dispersion on copper nanoparticles remarkably enhances the catalytic conversion and selectivity of hydrogen evolution. (C) 2014 Elsevier B.V. All rights reserved.