Preparation and Characterization of TiO2 Nanotube Arrays in Ionic Liquid for Water Splitting

Author(s)

Freitas, R. G. ^[1] ; Santanna, M. A. ^[1] ; Pereira, E. C. ^[1]

Affiliation

^[1] Univ Fed Sao Carlos, Dept Quim, NANOFAEL LIEC, BR-13565905 Sao Carlos, SP - Brazil

• Document type: Journal article
• Source: Electrochimica Acta; v. 136, p. 404-411, AUG 1 2014.
• Web of Science Citations: 22

Abstract

In the present work, it is described the fabrication and characterization of TiO2 nantotubes prepared potentiostatically using 1.0 or 5.0 vol.% ionic liquid electrolyte medium at 10 or 20 degrees C. These experimental conditions led to TiO2 nanotubes with 63-77 nm pore diameter, crystallite sizes between 27-33 nm, and band-gap values in the 3.1-3.2 eV range. Although the morphology and band-gap values were similar, the water splitting reaction showed differences in terms of photocurrent, up to 300%. Besides, we report also important changes in those parameters related with electronic defects, such as carrier density (N-D), width of depletion layer (w) and Debye length (lambda(D)). Then, the enhancement on photoelectrochemical properties could be related to a decrease in the rate of surface recombination processes. Finally, these proposition are in agreement with the open-circuit voltage-decay, where was observed a higher electron lifetime for TiO2NT obtained at higher vol.% of ionic liquid. (C) 2014 Elsevier Ltd. All rights reserved. (AU)

• FAPESP's process: 12/06778-0 - Electrochemical synthesis of TiO2 nanotubes and its anodic dopping
• Grantee: Milli Aline Sant Anna
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• FAPESP's process: 10/05555-2 - Electrochemical investigation of TiO2-nanotubes formation and its application on energy convertion nanostructured systems
• Grantee: Renato Garcia de Freitas Sobrinho
• Support Opportunities: Scholarships in Brazil - Post-Doctoral