This article presents a brief introduction about the six-membered-ring-based growth mechanism of carbon nanotubes (CNTs) with benzene precursor. The mechanism was successfully applied to the design and synthesis of N- or B-doped CNTs with corresponding heterocyclic precursors. The doped CNTs can act as the unique supports for the convenient construction of Pt-based nanocomposite catalysts with high dispersion, which show superior performance in electrocatalytic reactions of methanol oxidation and oxygen reduction. It is also revealed that doping with either electron-rich N or electron-deficient B could turn CNTs into the novel metal-free catalyst for oxygen reduction with excellent performance. These progresses provide the new idea and method for the design and development of the advanced electrocatalysts to make full use of or even substitute for the precious Pt species, which exhibits the great potential of carbon-based nanotubes in energy material field. The significance of the basic research on scientific innovation was also demonstrated through this study.