Flame Synthesis of Completely Graphitic Carbon Nanofibers and Nanofiber Composites Containing Encapsulated Metal Particles

University Of Illinois At Chicago, Chicago IL

Investigators

Abstract

FLAME SYNTHESIS OF COMPLETELY GRAPHITIC CARBON NANOFIBERS AND NANOFIBER COMPOSITES CONTAINING ENCAPSULATED METAL PARTICLES ABSTRACT This Small Grant for Exploratory Research pertains to the flame synthesis of completely graphitic carbon nanofibers that contain encapsulated metal particles. Carbon nanostructures, such as nanotubes and nanofibers, possess outstanding properties (capillarity, mechanical strength, metallic or semiconducting behavior, encapsulation of metal particles, and hydrogen storage capability). However, there are few technologies for producing bulk quantities of high-purity aligned nanotubes or nanofibers. The combustion synthesis of these nanomaterials is an attractive method. It has been shown that it is possible to encapsulate periodic metal deposits in the nanofibers. Nanostructures containing catalytic particles could serve as efficient nanoscale reactors. The encapsulation of metal particles may also make it possible to physically or chemically functionalize CNFs for useful purposes, and to form connected CNF networks. The objective of the proposed project is to encapsulate a variety of metal nanoparticles in completely graphitic nanofibers and nanofiber networks that are produced through flame synthesis. The study examines if: (1) completely graphitic carbon nanofibers of specified length and helicity can be synthesized as pure species both with and without heterojunctions (that enable nanofiber networks); (2) self-assembly techniques can be developed, say by using a variety of catalyst substrates, to control relative arrangements of nanoscale components to enable predesigned arrangements and morphologies; and (3) it is possible to characterize the processes that lead to economic preparation of nanostructures with control over size and shape for applications. The reactor used stabilizes a fuel-rich flame at the exit of a porous-media burner. The hot pyrolysis gases impinge on a substrate. The experimental matrix that influences the flame synthesis of these nanomaterials includes the substrate material, fuel/air equivalence ratio, substrate temperature, and the flow velocity and residence time. Broader impact This project has economic implications as well as those for the enhancement of knowledge. Although research on carbon nanostructures is a fast-moving field, commercialization is hampered by the lack of methods to economically produce the material in bulk. The understanding of the flame synthesis of ordered carbon nanostructures, such as CNFs and CNTs, is still at an early stage. The project contributes to the education of an NSF graduate fellow and the academic and research training of a research associate.