Multi-layered fullerenes, known as "carbon nano-onions," are attractive for various applications due to their shape, size, and surface area. A standard method usually uses powder catalysts, which require an additional step to separate and purify nano-onions after their synthesis. In this work, a simple method based on chemical vapor deposition and a copper foil as a catalyst has been developed. The effect of growth time on the structural, chemical, and morphological properties of nano-onions was investigated. The results indicate that carbon nano-onions with different degrees of graphitization, diameters, and thermal stability are obtained independently of the growth time.