Single- and Multi-wall Carbon Nanotube Growth on Nanoscale Zirconia and Other Oxides as Non-metallic Catalysts
- Category: Nanotechnology
- Tags: akira kudo, brian wardle
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Download as PDFThis work focuses on the development of non-metallic nanoparticles (NPs) that can catalyze carbon nanofiber (CNF) and nanotube (CNT) growth and the optimal conditions to obtain the best CNT growth yield utilizing such non-metallic substances. In our group’s previous work[1], we successfully demonstrated that a non-metallic catalyst, a zirconia nanoparticle, can catalyze CNT growth by thermal chemical vapor deposition (CVD) while remaining in an oxidized state. This novel class of catalyst for CNT growth will impact the potential to grow CNTs on historically challenging substrates, further expanding applications of CNTs. Since this discovery, we are studying CNT growth process for which qualitative models are suggested[2], especially at the atomic scale using a high-resolution transmission electron microscope (HR-TEM).
In order to smoothly perform our parametric approach, we have built a new CVD reactor and mass-flow controller array system (Figure 1). MANGO-TANGO, the acronym for Mass-flow controllers Array for Nanotube Growth Optimization and Table-top Apparatus for Nanotube Growth Optimization, has versatile capabilities such as handling twelve gas species at once, precise measurement of reaction spot temperature, and selective thermal treatment of gas species.
It has been observed that details of the NP affect morphology of the resulting CNF/T even though the non-metallic catalysts are the same substance. For example, both ready-made zirconia NPs and zirconium oxychloride solution work as good sources of catalysts, but their growth morphologies are substantially different (Figure 2). Currently HR-TEM is being used to investigate the origin of these different morphologies.
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- Figure 1: Schematic of MANGO-TANGO equipment[3].
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- Figure 2: CNTs grown on carbon aerogels with ready-made zirconia nanoparticles (left) and with zirconium oxychloride (right). Ready-made zirconium nanoparticles grew thick and short CNTs, while zirconium oxychloride grew thin and long CNTs[3].
- S. A. Steiner, et. al., “Nanoscale Zirconia as a Nonmetallic Catalyst for Graphitization of Carbon and Growth of Single- and Multiwall Carbon Nanotubes”, J Am Chem Soc, 131 (2009)1 2144-12154. [↩]
- L. L. Tan, et. al., “Growth of carbon nanotubes over non-metallic based catalysts: A review on the recent developments” Catal. Today, to be published. [↩]
- S. A. Steiner III, Ph.D. dissertation, Massachusetts Institute of Technology, Cambridge, 2012. [↩] [↩]