(A) study on the controlled synthesis of the carbon nanostructure: nanoparticle hybridization and application

Abstract

Recently, one-dimensional carbon nanostructures, including carbon nanotubes (CNTs) and graphene nanoribbons (GNRs), have exhibited their remarkable physicochemical properties with conspicuous aspect ratios. Also, the unique features of zero-dimensional nanoparticles (NPs) have been intriguing in state-of-the-art research fields. In addition, the new functional materials hybridized with different dimensionalities such as zero-dimensional NPs and one-dimensional carbon nanostructures have been demonstrated to result in their synergic performance for promising applications. However, facile synthesis of the hybrid, and also understanding of interaction between nanoparticles and CNTs are still challenging. In this study, the nitrogen doped CNTs were synthesized, so called carbon nitride nanotubes (CNNTs), to control their inner-structures and surface chemical states with different growth catalysts. The incorporated nitrogen atoms are dopants, which are extrinsic defects and heterogeneous nucleation sites of the NPs in the CNT matrix. From the controlled growth of CNNTs, the nitrogen doped graphene nanoribbons (NGNRs) have been synthesized with unzipping process. In chapter II, the CNNTs were fabricated with iron and cobalt catalysts to control their inner-structure and surface chemical state. The systematic X-ray photoelectron spectroscopy (XPS) and X-ray absorption fine structure (NEXAFS) analyses have been conducted to investigate nitrogen behavior in the carbon matrix. Additionally, enhancement of metal adsorption stability is also anticipated by extrinsically doped element. To under-stand how nitrogen atoms contribute the NPs anchoring on the carbon nanotubes, the X-ray absorption spectroscopy (XAS) and partial density of states (PDOS) analysis of nitrogen atoms in carbon nanotubes was studied. The nanoparticle-carbon nanotube nanostructures (Ni, Co, $Fe_3O_4$, $TiO_2$, $SnO_2$, Pt, Au, Au/$Fe_3O_4$, and CoPt) were fabricated without chemical functionallization ...