Self-doped TiO2 nanotube electrodes: A powerful tool as a sensor platform for electroanalytical applications

Made available in DSpace on 2018-12-11T17:31:52Z (GMT). No. of bitstreams: 0 Previous issue date: 2017-05-01 Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) The use of TiO2 nanotube (TiO2NTs) electrodes as anodes without UV irradiation has been described herein for electroanalytical purposes. Although semiconductors of n-type, such as TiO2NTs, do not offer any potential electrochemical response at the anodic region, they can be “activated” once they are a priori subjected to a simple cathodic polarization (P-TiO2NTs) and used to follow the oxidation reaction without any other modification. The best polarization conditions were obtained at 0.1 mol L−1 KH2PO4 pH 10 at −2.5 V for 5 min, and the polarized TiO2 electrode was applied in the Fe(CN)6 4− redox probe oxidation and also p-phenylenediamine (PPD) determination as models of species which undergo oxidation. Following the optimization of the parameters, analytical curves for Fe(CN)6 4− and PPD were constructed in the range of 2.5 × 10−5 to 5 × 10−3 mol L−1 with a detection limit at 7.23 × 10−6 mol L−1 and 0.500 to 98.6 × 10−6 mol L−1 with a detection limit at 0.558 × 10−7 mol L−1 using linear sweep voltammetry and linear sweep adsorptive stripping voltammetry techniques, respectively. Lastly, the figures of merit for P-TiO2NT and conventional glassy carbon electrodes are compared. Our results show that P-TiO2NT electrodes can be used as an excellent platform for the development of electrochemical sensors. Universidade Estadual Paulista (Unesp) Instituto de Química Araraquara, Av. Prof. Francisco Degni, 55 Universidade Estadual Paulista (Unesp) Instituto de Química Araraquara, Av. Prof. Francisco Degni, 55 CNPq: 153169/2014-1 CNPq: 446245/2014-3