Palladium nanoparticles supported on activated carbon were prepared by N-2 glow discharge plasma reduction (PdNPs/C-P) and a chemical reduction method using L-ascorbic acid as the reducing agent (PdNPs/C-V). PdNPs/C-P have a smaller particle size and higher metal dispersion than PdNPs/C-V. PdNPs/C-P afforded a 98% yield for the Suzuki coupling reaction of 4-bromotoluene with phenylboronic acid at a very low loading of Pd (0.5 mmol % Pd) and could be reused five times without an obvious reduction in catalytic activity.