• PDF / 470,477 Bytes
• 8 Pages / 432 x 648 pts Page_size
• 33 Downloads / 189 Views

DOWNLOAD

REPORT

---

Electrochemical Characterization of TiO 2 Nanotubular Films Exposed in an Aqueous Solution with a pH = 3.2 S. Mejía Sintillo1, C. Cuevas Arteaga1*, R. Ma. Melgoza Alemán2, P. Mijaylova Nacheva3 1 Instituto de Investigaciones en Ciencias Básicas y Aplicadas-Universidad Autónoma del Estado de Morelos, Av. Universidad 1001, Col. Chamilpa, C.P. 62209, Cuernavaca, Mor., México. 2 Facultad de Ciencias Químicas e Ingeniería-Universidad Autónoma del Estado de Morelos. 3 Instituto Mexicano de Tecnología del Agua, Postgrado en Ingeniería Ambiental de la UNAMCampus IMTA, Blvd. Paseo Cuauhnahuac 8532, Progreso, 62550 Jiutepec, Mor., México. *Corresponding Author. ABSTRACT TiO 2 nanotubular structures were fabricated on Ti polished and unpolished foils exposed to H 2 O-Glycerol (50-50Vol.%)+0.27 M NH 4 F at 20V. The obtained TiO 2 nanostructures were analyzed by SEM obtaining the morphological characterization, from which the roughness factors were calculated. Crystalline phases of both TiO 2 nanotubular films were obtained by XRD after annealing at 450 °C and 600 °C for 2 h. The electrochemical stability of the TiO 2 nanotubular films was obtained from the potentiodynamic polarization curves (PC) and the linear polarization resistance (Lpr) techniques, exposing the samples in 1M Na 2 SO 4 + H 2 SO 4 solution (pH = 3.2), such pH is in accordance with the acidic wastewater containing sulfur compounds coming from the industries or acid waters of the aquifers, which have been contaminated from the volcanoes nearby. It was concluded that the electrochemical stability of the crystallized nanotubular films is improved with the increase of the annealing temperature of the amorphous TiO 2 arrays, which is associated to the higher composition of anatase and rutile, observing that the major amount of rutile improved the corrosion performance. The photoelectrochemical measurements were carried out in 0.5 M Na 2 SO 4 VROXWLRQXVLQJDQ:89ODPSDWDȜ  nm, whose results were recorded at zero bias during 10 min under darkness and illumination intervals of 1 min each. The obtained results were in agreement with the necessary features for being used in photocatalytic water remediation.

INTRODUCTION Usually, the nanostructured materials arrays are scaled in the range of 1x10-9 m, however some authors have reported nanomaterials architectures around 1 micron. Nowadays, many scientific researchers have focused on the fabrication of unidimensional (1D) arrays. Nevertheless, in order to control the geometric features of these nanostructures and make them efficient for diverse applications, many affords have been made utilizing different electrolytes and applying a great interval of potentials, which has been a complex task [1-3]. Many scientists have been interested in the TiO 2 nanostructures around the world, which is due to their multiple applications in different areas of science and technology, for instance in medicine, biology, photo-catalysis, water splitting, optical and electronic devises, among others. For instance, the decomposit