In this paper we demonstrate the hydrogenolysis of nickelocene can take place through a self-catalyzed process at low temperature (< 70 degrees C) in supercritical carbon dioxide to generate relatively uniform dispersed Ni (nickel) metal particles onto carbon nanotubes forests and Ni films on flat surfaces. The ability to form metal particles or films without a local catalyst at this low temperature is significant because it provides further insight into mechanisms for Ni deposition reactions, and it enables a new route for low-temperature metal coating on a range of nonmetal substrate materials with complex topographies and nanostructures, for example, to form Ni/polymer magnetic nanocomposites. (C) 2008 The Electrochemical Society.