Fabrication Of Carbon Nanotube/Polypyrrole/Metal Oxide Composite Nanowires And The Study Of Their Catalytic Properties

Carbon nanotube is one kind of one-dimensional nanomaterials with excellentmechanical and electrical properties. It could be used as good supporting material, aswell as conducting media. In recent years, polypyrrole attracts more and moreattention because of its good biocompatibility. A synergistic effect is believed toaccelerate the transfer of electrons when combining carbon nanotube and polypyrrole.Therefore, the composite material has a wide range of applications in various catalyticreactions involved in electron transfer.This paper prepared carbon CNT/PPy composite nanowires by a self-assemblymethod. Then we fabricated two kinds of ternary composite nanowires containingmetal oxide based on this supporting material. First, CNT/PPy/KxMnO₂nanowireshave been fabricated and they performed well in detecting H₂O₂in PBS. Second, wehave successfully synthesized CNT/PPy/TiO₂ternary composite nanowires via ahydrothermal treatment. We have tested the photocatalytic performance of threesamples with addition of different contents of Ti precursor. The conclusions are asfollows:1. CNT/PPy/KxMnO₂, a novel ternary core–shell nanowires, was successfullyprepared by a two-step self-assembly method and utilized as an electrocatalyst for theoxidation of hydrogen peroxide. The results exhibited that the KxMnO₂nanosheets were grown on the surface of CNT/PPy core–shell nanotubes. The planes of theKxMnO₂nanosheets were more or less perpendicular to the CNT/PPy nanotubes.Cyclic voltammetry （CV） results demonstrated that the CNT/PPy/KxMnO₂compositenanowires, as a nonenzyme catalyst, performed well with regards to the oxidation ofhydrogen peroxide in0.1M phosphate buffer solution （pH7.0）. The composite had afast response with a linear range of5.0μM to9.7mM and a relatively low detectionlimit of2.4μM （S/N=3）. The sensitivity of the sensor for H₂O₂was114.6μA mM1cm2. These excellent properties might be due to the large surface area of thecomposite nanowires and the quick electron transfer promoted by the combination ofCNT and PPy.2. Using [CH₃（CH₂）3O]4Ti as Ti precursor, we have fabricated CNT/PPy/TiO₂ternary nanowires via a hydrothermal treatment based on CNT/PPy nanocomposites.The morphology characterization shows that TiO₂nanoparticles grew uniformly onthe surface of supporting materials. Through changing the contents of Ti precursor, wefabricated three kinds of photocatalysts with different Ti contents. The photocatalytictests indicated that all the three samples could be stimulated by visible light, due tothe introducing of CNT and PPy. Under the illumination of visible light, all the threesamples could degrade Rhodamine B in some degree. The sample made from30μLTi precursor performs best in degradation of Rhodamine B. After8hours’illumination, about72%Rhodamin B has been decomposited by CNT/PPy/TiO₂nanowires.