Surface properties of carbon micro-coils oxidized by a low concentration of oxygen gas

Vapor-grown carbon micro-coils were oxidized under a low O-2 flow-rate for introducing oxygen-containing functional groups on the surface. The surface characteristics were then examined. The O1s/C1s intensity ratios of the XPS spectra measured on the surface increased on using the oxidation treatment. The maximum O1s/C1s ratio of 11.4 at.% was obtained under the following conditions: (a) the flow-rate of the mixed gas of O-2+Ar (O-2/Ar=1/10) was 82.5 seem; (b) the oxidation temperature was 600 degreesC; and (c) the treatment time was 30 min. The maximum O1s/C1s ratio is about 3.5 times that of the source carbon coils. The specific surface area significantly increased due to the oxidation treatment and attained a maximum value of 1050 m(2) g(-1), which is about 10 times that of the source carbon coils. As the specific surface area increased, the surface morphology of the carbon coils became more complicated on a nanometer scale. (C) 2000 Elsevier Science Ltd. All rights reserved.