By doping various compounds, which can dissociate free radicals covalently bonding with carbon clusters, into the carbon target, C-60(+) and other fullerene ions were produced from direct laser vaporization. The compounds do not provide the carbon atoms, and to exhibit the promotion effect, only very small amounts of the species need to be doped, so the free radicals dissociated from the compounds behaved as catalysts in the formation process of the fullerenes. Among the various free radicals, free chlorine atom was found to be most effective in promoting fullerene formation. After doping the compounds, fullerene ions can be created from different forms of carbons, such as amorphous carbon, glassy carbon, graphite, and even diamond. Based on the experimental results, the catalysis mechanism of the free radicals and the formation process of fullerenes are suggested.