Preparation and Characteristics of SiO(x) Coated Carbon Nanotubes with High Surface Area

An easy method to synthesize SiO(x) coated carbon nanotubes (SiO(x)-CNT) through thermal decomposition of polycarbomethylsilane adsorbed on the surface of CNTs is reported. Physical properties of SiO(x)-CNT samples depending on various Si contents and synthesis conditions are examined by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), nitrogen isotherm, scanning electron microscope (SEM), and transmission electron microscope (TEM). Morphology of the SiO(x)-CNT appears to be perfectly identical to that of the pristine CNT. It is confirmed that SiO(x) is formed in a thin layer of approximately 1 nm thickness over the surface of CNTs. The specific surface area is significantly increased by the coating, because thin layer of SiO(x) is highly porous. The surface properties such as porosity and thickness of SiO(x) layers are found to be controlled by SiO(x) contents and heat treatment conditions. The preparation method in this study is to provide useful nano-hybrid composite materials with multi-functional surface properties.