N-Dopant-Mediated Growth of Metal Oxide Nanoparticles on Carbon Nanotubes

Metal oxide nanoparticles supported on heteroatom-doped graphitic surfaces have been pursued for several decades for a wide spectrum of applications. Despite extensive research on functional metal oxide nanoparticle/doped carbon nanomaterial hybrids, the role of the heteroatom dopant in the hybridization process of doped carbon nanomaterials has been overlooked. Here, the direct growth of MnO_x and RuO_x nanoparticles in nitrogen (N)-doped sites of carbon nanotubes (NCNTs) is presented. The quaternary nitrogen (N_Q) sites of CNTs actively participate in the nucleation and growth of the metal nanoparticles. The evenly distributed N_Q nucleation sites mediate the generation of uniformly dispersed <10 nm diameter MnO_x and RuO_x nanoparticles, directly decorated on NCNT surfaces. The electrochemical performance of the resultant hybridized materials was evaluated using cyclic voltammetry. This novel hybridization method using the dopant-mediated nucleation and growth of metal oxides suggests ways that heteroatom dopants can be utilized to optimize the structure, interface and corresponding properties of graphitic carbon-based hybrid materials.