Low pressure RF plasma modification of the surface of three different nano-carbon materials

Abstract

Well-ordered nano-carbon materials, like multiwall carbon nanotubes, graphene oxide, graphene due to their unique physical and chemical properties, are candidates for promising applications.In this work thin multilayered graphene, single layer graphene oxide layers and highly oriented pyrolytic graphite (HOPG) surface were treated by RF activated N 2 gas plasma at nominally room temperature. Negative bias in the 0-200 V range and treatment time of 10 min was applied. Surface chemical alterations were followed by X-ray photoelectron spectroscopy (XPS). The applied treatments resulted in a significant build-up of nitrogen in the surface of these nano-carbon materials. The amount of nitrogen varied between 4 and 10 atomic %, depending on type of carbon and on biasing conditions. Evaluating the high-resolution N1s XP spectral region, typically three different chemical bonding states of the nitrogen were delineated. Peak component at 398.3 eV is assigned to C=N-C type, at 399.7 eV to sp 2 N in melamine-type ring structure and at 400.9 eV to N substituting carbon in a graphite-like environment. Identical chemical bonding of the nitrogen was detected on the surface of HOPG treated in the same way for comparison.

Modification of graphene‐oxide surface in nitrogen and argon glow discharge plasma

“…Experiments, performed using similar conditions on other nanocarbon materials (e.g. graphene, nanotubes, or graphite), showed that similar chemical states were developed, although with different quantitative distributions.…”

“…Reliability of the results published so far is often suffering from insufficient characterization of the modified surface. We have been conducting detailed studies on this topic …”