A solvent free process for the generation of strong, conducting carbon spheres by the thermal degradation of waste polyethylene terephthalate

Pol, Swati V.; Pol, Vilas G.; Sherman, Dov; Gedanken, Aharon

doi:10.1039/b819494g

Cited by 50 publications

(42 citation statements)

References 21 publications

(12 reference statements)

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“…These materials have found use as strengthening additives [18], pigments in inks (as seen in the patent by Belmont et al ) [19] and as cathodes in batteries [20]. The use of spheres as a strengthening additive has been further confirmed by studying their great mechanical strength [21].…”

Section: Carbon Nanospheresmentioning

confidence: 78%

The electrical transport properties of nitrogen doped carbon microspheres

Wright

Marsicano

Keartland

et al. 2014

Materials Chemistry and Physics

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A suite of four samples of nitrogen doped carbon microspheres, each with a different level of nitrogen dopant, was synthesised in a horizontal chemical vapour deposition reaction. The samples were characterized using scanning electron microscopy, Raman spectroscopy and electron paramagnetic resonance spectroscopy. Scanning electron microscopy showed that microspheres were produced by the reaction. Raman spectroscopy confirmed the graphitic nature of the samples. Electron paramagnetic resonance spectroscopy determined that nitrogen was present in the graphitic lattice and was used as a non-destructive technique to measure the amount of substitutional nitrogen present in the samples. In order to perform electrical transport measurements an automated magneto-transport measurement station was developed in the laboratory. This transport station was computer controlled and contained all of the necessary hardware and software required to perform magneto-electrical transport measurements. Variable temperature electrical transport measurements were performed on all samples to determine their conductive properties. Resistance measurements showed that two of the samples were semiconductors while the other two samples displayed a transition to metallic behaviour at higher temperatures. This transition can be ascribed to the thermal desorption of nitrogen dopant. Models were fitted to the data and the semiconducting behaviour is best explained by a model of fluctuation induced tunnelling while the metallic behaviour is best explained by a quasi-1 dimensional metallic term based on electron-phonon interactions. The IV characteristics of two of the samples display increasing non-linearity of the current's voltage dependence with decreasing temperature. The other two samples exhibit this behaviour at lower temperatures while higher temperature IV data displays a current saturation with increasing voltage. The same models used to explain the resistance measurements can be used to explain the IV characteristics data extremely well. The magnetoresistance data taken with the direction of current flow orientated both parallel and perpendicular to the field, show a transition from negative to positive magnetoresistance with decreasing temperature. The results of these experiments are inconclusive, as a theoretical model of magnetoresistance in systems that conduct via fluctuation induced tunnelling is not well defined. A comparison between the resistance measurements of all four samples was made to determine the effect of nitrogen doping on the samples' ii Abstract electronic transport properties. The result of this comparison was indeterminate. This was due to samples with identical nitrogen dopant levels displaying vastly different conductive properties and indicates that very strict synthesis conditions need to be adhered to in order to ensure sample quality. Resistance measurements were rerun on the two samples that displayed purely semiconducting behaviour to investigate the possibility of atmospheric doping. It was foun...

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Section: Carbon Nanospheresmentioning

confidence: 78%

The electrical transport properties of nitrogen doped carbon microspheres

Wright

Marsicano

Keartland

et al. 2014

Materials Chemistry and Physics

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“…The tensile strength of a CS was measured under a compressive load and showed linear behaviour with time until the sphere fractured. 36,39,47 Hollow spheres have also been exploited and have been used in rechargeable batteries, in the protection of proteins and enzymes, gene and drug delivery, hydrogen storage, catalysis, sensing, and fuel cell electrodes. 48 …”

Section: Properties and Uses Of Spherical Carbonsmentioning

confidence: 99%

“…Recent studies have shown that 'ultrastrong' spherically shaped materials can be made. Pol et al 47 synthesised CSs from polyethylene terephthalate in an autoclave at 700 °C. The 2 mm -10 mm solid spheres reportedly 'broke one diamond knife and damaged a second' during microtome measurements.…”

Section: Properties and Uses Of Spherical Carbonsmentioning

confidence: 99%

A review of shaped carbon nanomaterials

Coville¹,

Mhlanga²,

Nxumalo³

et al. 2011

S Afr J Sci

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Materials made of carbon that can be synthesised and characterised at the nano level have become a mainstay in the nanotechnology arena. These carbon materials can have a remarkable range of morphologies. They can have structures that are either hollow or filled and can take many shapes, as evidenced by the well-documented families of fullerenes and carbon nanotubes. However, these are but two of the shapes that carbon can form at the nano level. In this review we outline the types of shaped carbons that can be produced by simple synthetic procedures, focusing on spheres, tubes or fibres, and helices. Their mechanisms of formation and uses are also described.

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“…[42] An efficient, solvent-free, catalyst-free approach was reported for the synthesis of carbon microspheres by thermal decomposition of waste PET in a closed reactor under autogenic pressure yielded exceptionally hard spherical (2 to 10 μm diameters) solid carbon bodies, with the average tensile strength for a single (~6 μm diameter) carbon sphere calculated to be 8.30±0.69 GPa. [43] A solvent free approach with catalyst was developed to produce large scale of carbon microspheres with 100% purity, using various waste plastics, such as PP, PE. Without any post treatment, the carbon spheres have been successfully utilized as the template for the synthesis of nanocrystalline CuO hollow spheres.…”

Section: Waste Plastics As Low Cost Feedstocks For Carbon Materialsmentioning

confidence: 99%

“…[44] Figure 2 SEM images of various carbon spheres: (a) dissociating PET in a supercritical CO2 system; [41] (b) thermal decomposition of waste PP; [44] (c) thermal decomposition of waste PE; [42] thermal decomposition of waste PET in a closed reactor. [43] Preparation of porous carbon materials…”

Section: Waste Plastics As Low Cost Feedstocks For Carbon Materialsmentioning

confidence: 99%

Converting Waste Plastics into High Yield and Quality Carbon-Based Materials

Kong¹,

Yang²,

Zhang³

et al. 2017

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Recycling waste plastics including polypropylene, polyethylene, polyethylene terephthalate, polystyrene, etc, is a very important scientific, social and economic topic. Despite significant advances in recent years, approximately 400 million tons of waste plastics are still disposed by landfill. This is obviously not an effective solution due to plastic's non-biodegradable character. Aside from mechanical recycling, which turns waste plastics into new products, and thermal recycling, which releases the thermal energy through combustion of waste plastics, chemical recycling converts waste plastics into feedstock for chemicals/materials/fuels production. This article reviews previous work on the pyrolysis and catalytic decomposition route that converted plastics into carbon-based materials, which exhibited extraordinary physical and chemical properties. However, their production processes are both resource and energy-intensive. Therefore, recycling technologies for waste plastics are still at an early stage and more innovation in waste plastic recycling is needed.

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A solvent free process for the generation of strong, conducting carbon spheres by the thermal degradation of waste polyethylene terephthalate

Cited by 50 publications

References 21 publications

The electrical transport properties of nitrogen doped carbon microspheres

The electrical transport properties of nitrogen doped carbon microspheres

A review of shaped carbon nanomaterials

Converting Waste Plastics into High Yield and Quality Carbon-Based Materials

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