Study On The Preparation And Properties Of Functionalized Carbon Nanotubes

Since their discovery in 1991, carbon nanotubes (MWNTs) have captured the imagination of scientistsworld-wide due to their unique structural,physical chemistry properties and electronic properties. The remarkable electrochemistry properties of MWNTs are useful for the electrochemical sensors.As well known, the applications of MWNTs have been limited due to the properties of MWNTs which tend to aggregate and difficultly separate in most solvents. In this work, in order to impove the dispersion of MWNTs, we have tried to chemically functionalize the MWNTs. First, the noncovalence functionalization of MWNTs with sodium alginate (SA), the functionalized MWNTs could form stable uniformly dispersed black water solution, and form uniform three-dimensional reticular structure on the solid substrate and increase the surface area of substrate. The SA-MWNTs composite film retained the similar structure of hemoglobin (Hb), and the Hb entrapped in the composite film could achieved the direct electron transfer between Hb and SA-MWNTs modified electrode, with the electron transfer rate constant of (9.54±0.883) s-1. The Hb adsorbed onto the composite film had excellent bioelectrocatalytic activity to the reduction of hydrogen peroxide. The biosensor constructed in this way has much possibility in usage.We intentionally introduced carboxyl group and synthesized hydroxyapatite (HA) by self-assembly method via an aqueous solution reaction. It is found that the MWNTs-HA could form stable uniformly dispersed black water solution, and form uniform three-dimensional reticular structure on the solid substrate. The MWNTs-HA composite film retained the similar structure of hemoglobin (Hb), and the Hb entrapped in the composite film could achieved the direct electron transfer between Hb and MWNTs-HA modified electrode, with the electron transfer rate constant of (5.05±0.41) s-1. The Hb adsorbed onto the composite film had excellent bioelectrocatalytic activity to the reduction of hydrogen peroxide and TCA.We further studied direct electron transfer of glucose oxidase and laccase on the MWNTs-HA composite film, and prepared a novel (MWNTs-HA) nanocomposite-based compartment-less glucose/O2 biofuel cell with the glucose oxygen as the anodic biocatalysts and the laccase as the cathodic biocatalysts. It is important for the new biofull cell.