Investigation on optical and photoelectrochemical properties of self-assembled titania nanotube arrays prepared by anodization; [Penyiasatan sifat optik dan fotoelektrokimia swahimpunan nanotiub titania bertatasusunan yang disediakan melalui penganodan]

• Published in: Malaysian Journal of Analytical Sciences
• Main Author: Chin L.Y.; Zainal Z.; Hussein M.Z.; Tee T.W.
• Format: Article
• Language: English
• Published: Malaysian Society of Analytical Sciences 2016
• Online Access: https://www.scopus.com/inward/record.uri?eid=2-s2.0-84958533970&doi=10.17576%2fmjas-2016-2001-13&partnerID=40&md5=be9fa96776d9b038ce4d3a6209d5996e

Well ordered and vertically oriented titania nanotubes (TNT) are of great scientific interest due to their high surface area, fewer interfacial grain boundaries and excellent charge transfer between interfaces; all are critical properties in photoelectrochemical and photocatalysis application. In this study, self-assembled TNT electrodes were synthesized by anodization of pure Ti in 0.5 wt.% NH4F solution (NH4F/H2O), in mixture of aqueous-organic solution (NH4F/H2O/EG) and in an organic solution (NH4F/EG). Choice of electrolytic medium has an influence on the crystalline structure, regularity, elemental composition and band gap of TNT. All the samples showed a red shift and stronger absorption in the wavelength between 500-700 nm ascribed to the surface colour and increase crystallinity upon calcination. TNT formed in NH4F/H2O solution has the highest direct band gap of 3.34 eV due to quantization effect. From Liner Sweep Photovoltammetry analysis, the lowest photocurrent was recorded for TNT anodized in NH4F/H2O and a twofold and fivefold increase on the magnitude of photocurrent was obtained for those formed in NH4F/H2O/EG and NH4F/EG solution, respectively. Hence, highest photoefficiency of 2.79 % was recorded for TNT formed in NH4F/EG probably due to the formation of longer length tube. © 2016, Malaysian Society of Analytical Sciences. All rights reserved.