Electrodeposited polyaniline on Pd-loaded TiO2 nanotubes as active material for electrochemical supercapacitor

PANI/Pd/TiO2NTs electrodes with highly porous structures and good capacitive characteristics were prepared by electrodeposition of polyaniline on palladium nanoparticles loaded TiO2 nanotubes. The loading of small palladium nanoparticles was carried out by sonochemical reduction of Pd+2 onto TiO2NTs and affected the ordered growth of PANI, reducing the charge transfer resistance and increasing surface area of PANI. The specific capacitance and the stability of electrode showed improvements. The results illustrated that the specific capacitance of these electrodes was around 1060 F g(-1) in 1.0 M H2SO4 electrolyte as measured at a constant current of 2.0 A g(-1), whereas it was 210 F g(-1) for the PANI/TiO2NTs electrode. The modified electrodes also showed high stability and maintained 94% of initial capacity in 1.0 M H2SO4 electrolyte after 10 days being used in electrochemical experiments. The results were confirmed by impedance studies and equivalent circuit compatible with the findings is proposed. (C) 2012 Elsevier B.V. All rights reserved.