The development of nanoscale supports for metal catalysts is critical for advancing heterogeneous catalysis and fuel cell electrodes. In this study, we used graphite nanofibers (GNFs, with various graphite sheet orientations: herringbone, ribbon, and platelet) as particle supports. Our process for loading the GNFs started with the complexation of Pd and Cu complexes. We initially explored 1,1,1-trifluoro-2,4-pentanedione (tfacH) and 1,1,1,5,5,5-hexafluoro-2,4-pentanedione (hfacH) as the ligands to produce the complexes: Pd(tfac)2, Pd(hfac)2, Cu(tfac)2, and Cu(hfac)2. These transition metal complexes were selected because they 1) dissolve readily in supercritical CO2, and 2) decompose easily at elevated temperatures, allowing the metals to deposit on the nanofibers. Hydrogen was selected as the reductant due to its complete miscibility in supercritical CO2. The metal particle size was controlled via the temperature, pressure, and reactant concentrations. The concentrations of each metal complex and H2 were varied and their effects on particle formation examined by SEM and TEM.