The preparation and characterization of electrochemical reduced TiO 2 nanotubes/polypyrrole as supercapacitor electrode material

A hybrid material of electrochemical reduced TiO 2 nanotubes/polypyrrole (r-TiO 2 NTs/PPy) was successfully prepared through electrochemical reduction and deposition method. The r-TiO 2 NTs were fabricated by electrochemical reduced TiO 2 nanotubes after anodizing Ti in an aqueous solution containing ammonium fluoride, phosphoric acid, and ethylene glycol. The r-TiO 2 NTs/PPy were then prepared by potentiostatic deposition process in an aqueous solution containing pyrrole monomer and lithium perchlorate. The morphology and microstructure of r-TiO 2 NTs/PPy were characterized by scanning electron microscopy, X-ray diffraction, and Raman spectroscopy, and the results indicated that the polypyrrole was electropolymerized and deposited on r-TiO 2 NTs. The electrochemical capacitance performance was determined by cyclic voltammetry and charge–discharge measurement. The electrochemical test, carried out in an electrolyte of 1 mol/L H 2 SO 4 during the galvanostatic charge–discharge cycles, showed that the nanocomposite had a specific capacitance of 896.65 F g −1 at a current density of 0.5 A g −1 in a potential range of −0.2∼0.4 V, which was superior to that of TiO 2 NTs and r-TiO 2 NTs. The significant improvement in electrochemical performance of the composite material prepared in this work could be attributed to the conductivity of r-TiO 2 NTs and pseudocapacitance performance of polypyrrole.