Carbon-encapsulated metal nanoparticles (CEMNs) were obtained by the catalytic decomposition of hydrocarbons (CH4, C2H6, C2H4) on nanocrystalline nickel. Nanocrystalline nickel was obtained by precipitation from nickel nitrate solution, followed by calcination and reduction under hydrogen. A small amount of structural promoters (aluminium and calcium oxide) was added to avoid recrystallisation of fine nickel particles at elevated temperatures. Reduction and carburisation of the samples was carried out in a differential reactor with mass control. The rate of decomposition of methane, ethane and ethylene on nanocrystalline nickel was measured and the apparent activation energy of the process was determined. The obtained samples were characterised using the XRD, SEM and HRTEM methods. (C) 2009 Elsevier B.V. All rights reserved.