Carbon-, Gold- and Iron-based Nanomaterials – Synthesis, Characterization and Potential Applications

• Author / Creator

  Hadidi, Lida

• Nanomaterials are important building blocks of nanotechnology. Their size dependent unique properties (optical, magnetic, electrical, etc.) have the potential to revolutionize applications ranging from medicine to electronics. Of the various nanomaterials, carbon-based systems including porous carbon, graphene, graphite nanofibers, and carbon nanotubes (CNTs) have received considerable attention due to their high surface area, limited toxicity, biocompatibility, electronic conductivity, chemical stability, and low density. Despite the development of different synthetic approaches for preparing various carbons, there is still vast interest in developing cost-effective scalable methods for the synthesis of carbon-based materials, in particular mesoporous carbons. Owing to their high surface area, carbon based materials have been extensively studied for catalytic applications. However, important challenges related to material synthesis remain. The research described in this dissertation attempts to address challenges associated with synthesis of mesoporous carbons as well as their prototype catalytic applications. The investigations then shift to the synthesis and applications of iron oxide nanorods coated with N-doped mesoporous carbon core-shell nanostructures as catalyst. Finally, the extension of photothermally responsive hybrid gold/silica nanoparticles into catalytic applications is explored. The thesis starts with an introduction summarizing the broad field of nanomaterials. Focus then shifts to the materials (i.e., mesoporous carbon, iron oxide nanoparticles and gold nanoparticles) specific to the presented investigation. Chapter Two outlines on synthesis of hollow mesoporous carbon (HMC) nanostructures using dopamine as carbon precursor. The HMC was fully characterized. The resulting HMC was employed as an electrocatalyst for oxygen reduction/evolution reactions (ORR/OER) in zinc air battery (ZAB). The HMCs exhibited outstanding ORR onset potential and excellent stability comparable to that of precious metal catalyst. Chapter Three presents the synthesis of high surface area hollow carbon spheres (HCS) using crystalline nanocellulose (CNC) as carbon precursor and a detailed investigation and discussion on the formation mechanism. The synthesized HCS were implemented for catalytic conversion of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP). The catalytic activity was investigated in terms reaction rate and activity parameter. The HCS exhibited remarkable catalytic activity comparable to that of their metallic nanoparticles counterparts. Chapter Four is extension of previous work where mesoporous carbon is used as a thin shell material. The synthesis of Fe3O4 nanorods coated with a nitrogen-doped mesoporous carbon shell (ND-Fe3O4@mC) via a new microwave-assisted approach is presented. The electrochemical performances of ND-Fe3O4@mC with different carbon shell thicknesses are evaluated. The results reveal enhanced ORR catalytic activity for the catalyst with thinnest carbon shell. The synthesis of different morphologies of gold nanostructures along with hybrid gold/silica nanoparticles is presented in Chapter Five. The optical properties of these structures are investigated in detail and co-related with structure. The application of silica decorated with gold nanoparticles investigated for catalytic conversion of 4-NP conversion to 4-AP. Finally, Chapter Six provides a summary of the conclusions of the work and outlines future work.

• Subjects / Keywords

  • Gold-based nanomaterials
  • Carbon-based nanomaterials
  • Iron-based nanomaterials

• Graduation date

  Spring 2016

• Type of Item

  Thesis

• Degree

  Doctor of Philosophy

• DOI

  https://doi.org/10.7939/R30000G5J

• License

  This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.