Deposition of an ultra-thin polyaniline coating on a TiO2 surface by vapor phase polymerization for electrochemical glucose sensing and photocatalytic degradation

Abstract

Here, we have synthesized an ultra-thin coating of polyaniline on a TiO₂ nanoparticle surface (PANI–TiO₂) using a simple vapor phase polymerization method. By this method, an ultra-thin layer of PANI is obtained selectively on the TiO₂ surface. This ultra-thin coating exhibits the properties of both the parent materials due to the composite surface causing an effective synergistic effect. SEM, TEM, and EDX studies and elemental mapping confirmed the formation of ultra-thin films on the TiO₂ surface. TGA, UV/Vis and XRD studies were also done for further characterization. The composite has been used as a biosensor for glucose detection by immobilization of the enzyme glucose oxidase (GOx). Cyclic voltammetry, electrochemical impedance spectroscopy and amperometry studies were performed for glucose sensing. The linear range was observed from 20 to 140 μM glucose concentration from the amperometric analysis. The LOD of the biosensor was found to be 5.33 μM. The composite has also been used for photocatalytic degradation of the cationic dye Rhodamine B (RB). The order of degradation efficiency of RB is found to be PANI < TiO₂ < PANI–TiO₂. The synergetic effect of PANI and TiO₂ is the reason for the enhanced degradation efficiency of the composite PANI–TiO₂.