title: Helical TiO2 Nanotube Arrays Modified by Cu-Cu2O with Ultrahigh Sensitivity for the Nonenzymatic Electro-oxidation of Glucose.
abstract: A novel Cu-Cu2O/TiO2/Ti electrode for the nonenzymatic electro-oxidation of glucose has been fabricated by secondary anodic oxidation combined with the electrodeposition method. It represents a new type of copper oxide-TiO2 complex nanostructure that demonstrates a new application. At the potential range from -1.0 to -1.6 V, Cu2+ was electrochemically reduced to Cu2O, accompanied by the simultaneous formation of Cu covering the top surface of the TiO2 nanotubes. The highest response current was obtained at the optimized fabrication conditions with a deposition charge of 1.5 C, a pH of 12, 4 mM CuSO4, and a deposition potential of -1.4 V. The results indicate that Cu2O helps to keep a broad linear range, and the incorporation of Cu nanoparticles improves the response current and sensitivity. The linearity between the response current and the glucose concentration was obtained in the range from 0.1 to 2.5 mM with a sensitivity of 4895 μA cm(-2) mM(-1). Such high sensitivity was attributed to the synergistic effect of the small Cu-Cu2O grain size and the large surface area of the helical TiO2 nanotube arrays as well as the fast electron transfer. Electrochemical impedance spectroscopy has been successfully applied to explain the differences among different electrode interfaces and the change rule of nonenzymatic electro-oxidation properties.
authors.affiliation: †School of Chemistry and Chemical Engineering, Central South University, Changsha 410083, China.|‡Department of Neuroscience, Physiology, and Pharmacology, University College London, Gower Street, London WC1E 6BT, U.K.
authors.forename: Qian
authors.initials: Q
authors.lastname: Yang
authors.affiliation: †School of Chemistry and Chemical Engineering, Central South University, Changsha 410083, China.
authors.forename: Mei
authors.initials: M
authors.lastname: Long
authors.affiliation: †School of Chemistry and Chemical Engineering, Central South University, Changsha 410083, China.
authors.forename: Lin
authors.initials: L
authors.lastname: Tan
authors.affiliation: §Department of Inorganic Materials, School of Resources Processing and Bioengineering, Central South University, Changsha 410083, China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: §Department of Inorganic Materials, School of Resources Processing and Bioengineering, Central South University, Changsha 410083, China.
authors.forename: Jin
authors.initials: J
authors.lastname: Ouyang
authors.affiliation: †School of Chemistry and Chemical Engineering, Central South University, Changsha 410083, China.
authors.forename: Ping
authors.initials: P
authors.lastname: Liu
authors.affiliation: †School of Chemistry and Chemical Engineering, Central South University, Changsha 410083, China.
authors.forename: Aidong
authors.initials: A
authors.lastname: Tang
mesh_terms: D015374:Biosensing Techniques / Q000379:methods*; D003300:Copper / Q000737:chemistry*; D058266:Dielectric Spectroscopy / Q000379:methods*; D004566:Electrodes; D005947:Glucose / Q000032:analysis*; D057230:Limit of Detection; D016014:Linear Models; D010084:Oxidation-Reduction; D015203:Reproducibility of Results; D014025:Titanium / Q000737:chemistry*
chemical_list: C009495:titanium dioxide; D003300:Copper; D014025:Titanium; D005947:Glucose; C000520:cuprous oxide
keywords: Cu−Cu2O nanoparticles; TiO2 nanotube arrays; electrochemical impedance spectroscopy; nonenzymatic electro-oxidation of glucose; sensor