title: Enhanced charge storage by the electrocatalytic effect of anodic TiO₂ nanotubes.
abstract: Ordered titania nanotube (TNT) arrays were fabricated by anodization of titanium with a very fast voltage ramp speed. Co(OH)(2)/TNT nanocomposite was synthesized by cathodic deposition using the as-anodized TNT as the substrate. Scanning electron microscopy (SEM), X-ray diffraction (XRD), Raman spectroscopy and X-ray photoelectron spectroscopy (XPS) were used to characterize the morphology, crystalline structure and chemical state. The capacitive characteristics were investigated by cyclic voltammetry (CV), charge-discharge tests, and electrochemical impedance spectroscopy (EIS). Thanks to the electrocatalytic effect of the as-anodized TNTs on the reduction of Co(OH)(2), the Co(OH)(2)/TNT composite electrode exhibits a significantly enhanced charge storage capacity (an increase of 73%) when compared with Co(OH)(2)/Ti (titanium as the deposition substrate). The occurrence of such an electrocatalytic effect is suggested to be related to the nano-sized TiO(2) crystals (rutile) embedded in organized amorphous TNTs. Co(OH)(2)/TNT demonstrates enhanced specific energy, high rate capability and good cyclability, and can be a potential electrode of choice for supercapacitors.
authors.affiliation: School of Materials Science and Engineering, South China University of Technology, Guangzhou, P. R. China.
authors.forename: Guoge
authors.initials: G
authors.lastname: Zhang
authors.forename: Chuanjun
authors.initials: C
authors.lastname: Huang
authors.forename: Limin
authors.initials: L
authors.lastname: Zhou
authors.forename: Lin
authors.initials: L
authors.lastname: Ye
authors.forename: Wenfang
authors.initials: W
authors.lastname: Li
authors.forename: Haitao
authors.initials: H
authors.lastname: Huang
mesh_terms: D002384:Catalysis; D003460:Crystallization; D055664:Electrochemical Techniques; D004566:Electrodes; D043942:Nanotubes / Q000737:chemistry*; D056951:Photoelectron Spectroscopy; D014025:Titanium / Q000737:chemistry*
chemical_list: C009495:titanium dioxide; D014025:Titanium