In Situ Carbon Nanotube Formation in Templated Pores of Polymer‐Derived Ceramics

Abstract

Multi‐walled carbon nanotubes (MWCNTs) have been formed in situ in porous, polymer derived ceramics, using polystyrene (PS) microbeads as pore formers. The microbeads were coated with nickel acetate, as a transition metal catalyst precursor, and then introduced into the preceramic polymer methylphenylpolysiloxane (PMPS). The PMPS served as a precursor for the ceramic matrix and as carbon source for CNT formation. The PS microbead burnout was observed between 200 and 400 °C, leaving behind nickel nanoparticles at the surface of the templated pore walls. Thermal conversion of the precursor to ceramic was carried out in the temperature range between 500 and 1 200 °C. MWCNTs were formed in the templated pores during the pyrolysis step by converting the carbon from the decomposition of PMPS. The oxidation resistance of these composites has been studied and an interesting catalytic oxidation phenomenon was observed that may be quite important for the oxidation of carbon nanotubes.

An optimized process for in situ formation of multi-walled carbon nanotubes in templated pores of polymer-derived silicon oxycarbide

“…3.d and it appears to be surrounded by the pyrolyzed SiOC matrix material, which corroborates the observation of nanostructure in the SEM images ( Fig. 3.a to 3.c).The dense and intertwined CNTs "forest" have almost fully covered the entire micro-porous fracture surfaces of all the examined samples, which is unlike what were foundthe observationsin many previous studies [17,21,23,31].From the close-up micrographs, it appears that the grown CNTs become longer and denser as PMMA-Ni content increases, however, no significant difference can be observed in terms of their general morphology. The CNT diameter ranges from ~50 to ~100 nm.…”

“…As shown in Fig. 3.d, the dark nanoparticles in the image are nickel [23] with size slightly less than 100 nm-a typical value for these particles to serve as seeds for the growth of CNT confirming the size of the grown CNTs as well. In addition, the "dense" wall and the hollow interior of the CNT structure can also be observed and confirmed in Fig.…”

“…Later, they showed the in situ growth of CNTs when nickel acetate and silicon were incorporated together into the PMPS precursor/silicon mixture [22]. In a related study, using polymeric microbeads as sacrificial pore formers, Terry et al showed the formation of CNTs in these templated pores [23].…”

Metal-Containing Ceramic Composite with in Situ Grown Carbon Nanotube as a Cathode Catalyst for Anion Exchange Membrane Fuel Cell and Rechargeable Zinc–Air Battery

“…The metal-containing ceramics show a strong diffraction peak at 26.2°related to graphitic carbon phase and not showing any H44 peaks. 15 In addition to these observations, the Ni-containing ceramics show the reflexes of intermetallic nickel silicide such as Ni 2 Si and Ni 31 Si 12 . 33 For Ni-containing ceramics even at 1000 °C, the Ni strongly favors the reduction of Si−O bonds and the forthright formation of nickel silicides.…”

A Novel Approach for the Processing of Advanced Polymer Derived Ceramics with Carbon Nanotubes with the Help of Pores

“…[11,15] The nanocrystalline SiC was formed in close proximity to the segregated carbon phase. [11,15] The nanocrystalline SiC was formed in close proximity to the segregated carbon phase.…”