The growth of carbon micro-trees by classical isothermal-isobaric chemical vapor deposition technique at 900 degrees C without any catalyst has been explored using propylene and hydrogen as the carbon source and the carrier gas, respectively. The morphology and the microstructure of the as-prepared carbon micro-trees were characterized using scanning electron microscopy, polarized light microscopy, Raman spectroscopy, and transmission electron microscope. The obtained carbon micro-trees had diameters of hundreds of microns and lengths up to 1 mm. They were composed of a central filament and an outer disordered carbon sheath. From these observations, a growth mechanism is proposed for the carbon micro-trees growth, in which axial self-assembling of carbon onions and radical thickening of pyrolytic carbons are involved. The influence of carrier gases and propylene partial pressure on the formation of the carbon micro-trees was investigated. It was found that both the hydrogen and the high concentration of propylene were favorable for the growth of the carbon micro-trees.
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