Iron oxide embedded on graphene oxide (Fe2O3/GO) was prepared by chemical exfoliation followed by wet impregnation. Reduced Fe2O3/GO could be employed as catalyst for synthesizing carbon nanotubes CNTs via catalytic chemical vapor deposition CCVD of n-hexane within a temperature range of 700-1000 degrees C. It was found that during the synthesis process, pretreatment affected the transformation of iron nanoparticles in the Fe2O3/GO, leading to significant difference in formation of carbon nanoparticles. When the Fe2O3/GO was employed within a temperature range of 700 900 degrees C, Fe2O3 was reduced to alpha-Fe, yielding CNT growth on the graphene surface. However, the alpha-Fe could be transformed to gamma-Fe when the Fe2O3/GO was subject to the temperature of 1000 degrees C, resulting in formation of carbon spheres instead of CNTs. After experimentally verified, conceptual scenarios of CNT/graphene hybrid material formation with respect to the pretreatment and synthesis temperature were proposed and discussed.