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Novel Catalyst for the Chirality Selective Synthesis of Single Walled Carbon Nanotubes
Final rept. 3 Apr 2013-2 Apr 2015
NANYANG TECHNOLOGICAL UNIV (SINGAPORE)
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Chiral single walled carbon nanotubes SWCNTs are known to possess unique electronic and optical properties. Common synthesis methods yield mixtures of SWCNTs thus making structure-property diversity a major hurdle in their use in applications. The aim of this project was to develop fundamental understanding of catalyst selectivity to achieve improved and tunable chirality control in SWCNT synthesis. A model catalyst based on CoSO4SiO2 was developed that showed good selectivity to 9,8 nanotubes. Remote plasma enhanced chemical vapor deposition was used to manipulate carbon radical generation in carbon precursors during synthesis. Water s influence on SWCNT diameter and yield was revealed for water-assisted ethanol pyrolysis,. Introducing sulfur-containing compounds into carbon precursors efficiently altered chiral selectivity toward different chiral SWCNTs. Selectivity could be tuned by varying calcination conditions, which affected the structure of sulfur near metal catalyst particles. Selective extraction of chiral SWCNT mixtures using fluorine-based polymers or aqueous two-phase separation was found to enrich the concentration of semiconducting 9,8 nanotubes. A scalable continuous method to produce carbon microfibres with hierarchical structures comprising nitrogen-doped reduced GO rGO and acidoxidized SWCNTs was produced using a linear hydrothermal microreactor. Fiber micro-supercapacitors based on these hybrid fibers show great potential for wearable electronics applications.
APPROVED FOR PUBLIC RELEASE