Synthesis Of One-dimensional Polyaniline Nanotube And Visible Light Photocatalytic Properties Of Its Complexes

Conducting polymers are interesting materials in modern technology because of their potential applications such as electromagnetic radiation shielding, antistatic coating and sensors. Polyaniline （PANI） is unique among the family of conjugated polyers due to its low cost, simple fabricating process, excellent conductivity and good chemical stability. One-dimensional （1D） nanomaterials exhibit special physical and chemical properties owning to their small size effect and surface effect. The synthesis and morphology controlling of PANI and its composites have become the subject of extensive studies. The synthesis of 1D PANI in nano-scale is one of the hottest research area. In addition, the study on the metal anti-corrosion, secondary batteries and wave-absorbing os PANI have achieved fruitful results, while the application of PANI on photocatalysis was rarely reported. In this paper we reported the synthesis of 1D PANI nanotubes and PANI/Fe³⁺ nanotubes. Also we have investigated the photocatalytic activity of PANI/Fe³⁺. The main contents are as follows,（1） Tungsten acid and citric acid codoped 1D square-like PANI nanotubes with diameter less than 100 nm have been successfully synthesized. The preparation method is simple and feasible, high yield, easy to promote to the industrial production. The structure and morphology of the materials was characterised by scanning electron microscopy （SEM） and infrared absorption analyzer （FT-IR）. The influence of the experiment conditions including pH value of the solution and the ratio of the tungsten acid to the aniline monomer on the final morphology and electrical conductivity of the materials have been investigated. The conductivity of square-like 1D PANI was 3.19×10-2 S/cm measured by four-probe conductivity instrument. The value was two orders of magnitude higher than undoped PANI.（2）For the first time, 1D circular nanotubes of PANI/Fe³⁺ using CTAB as soft template have been successfully obtained. The structure and morphology of the materials were characterised by SEM, FT-IR, TEM and EDS. Six contral experiments have been carried out to investigate the influence of various experimental factors on the morphology of the PANI/Fe³⁺, so as to propose rational growth mechanism of PANI/Fe³⁺. The conductivity of PANI/Fe³⁺ was confirmed to be excellent with the value of 1.075 S/cm.（3）The photocatalytic performance of the materials for the degradation of rhodamine B （RhB） was evaluated under visible-light irradiation （λ>420 nm）. The result showed that the circular PANI/Fe³⁺ composites had excellent photocatalytic efficiency and fast decomposition rate. It took only 26 minutes to degrade 100 mL RhB （2×10-5 moL/L） with only 10 mg of the samples. In addition, the cycle performance tests showed that it could be easily recycled without the decrease of the photocatalytic activity.