Investigating the influence of oxygen/carbon ratio on fabrication of composite carbon nanotubes by self-assembly surface treatment

Through self-assembly monolayer surface treatment, metal oxide nanoparticles uniformly dispersed onto carbon nanotubes (CNTs) surface are investigated. At first, oxidation treatment was performed to increase O/C ratio of CNTs surface at 250 degrees C for 1 hr under an oxygen atmosphere. X-ray photoelectron spectroscopy (XPS) analysis shows that O/C ratio is a increasing function of oxidating time. Distribution of oxygen functional groups on CNTs surface, i.e., carboxyl, carbonyl, phenolic groups, can be identified and deconvoluted by a symmetrical Gauss function. Experiments indicate that heat time for 5hr can produce a greater O/C ratio on CNTs surface. It is observed that carboxyl groups acts an important role to link with metal ions via an ionic interaction, thus, forming a monolayer adsorption on CNTs surface. By heating the treated CNTs, a completely composite nanostructure is thus formed. In the present work, we successfully fabricate three kinds of nanoparticles including SnO2, and RuO2, with an average diameter of 5-10 nm coated on the CNTs.