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

Jin Ah Lee,Won Jun Lee,Sang Ouk Kim,Joonwon Lim

doi:10.3390/nano11081882

Abstract

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 MnOx and RuOx nanoparticles in nitrogen (N)-doped sites of carbon nanotubes (NCNTs) is presented. The quaternary nitrogen (NQ) sites of CNTs actively participate in the nucleation and growth of the metal nanoparticles. The evenly distributed NQ nucleation sites mediate the generation of uniformly dispersed <10 nm diameter MnOx and RuOx 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.

Highlights

NCNTs were grown from iron (Fe) catalysts by using PECVD in a NH3 environment, which was used as a chemical source for the N-doping of carbon nanotubes (CNTs)
Strand and the distance between NCNTs were precisely controlled to ~20 nm and ~50 nm, respectively, by controlling the size and the location of Fe catalysts using a nano-template made of self-assembled cylindrical PS-b-PMMA block copolymer (BCP) (Figure S1)
After the desired reaction time, samples were washed with deionized water to remove unreacted residual precursors from the produced metal oxide nanoparticle and NCNT hybrids

Summary

Introduction

Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations. Substitutional heteroelement doping of graphitic carbon nanomaterials, including nitrogen (N), boron (B), sulfur (S) and fluorine (F), has been intensively investigated to control and optimize their structure and properties [1,2]. Such heterodopants can offer an opportunity for dramatic modifications in the electronic structure and chemical properties of graphitic carbon nanomaterials [3,4]. The modified surface properties of doped carbon nanomaterials have been widely exploited for nanocomposite synthesis

Methods

Results

Conclusion