Three-dimensional Gd-doped TiO 2 fibrous photoelectrodes for efficient visible light-driven photocatalytic performance

• Published in: RSC advances 2014, Vol.4 (23), p.11750-11757
• Main Authors: Choi, Junghyun, Sudhagar, P., Lakshmipathiraj, P., Lee, Jung Woo, Devadoss, Anitha, Lee, Sangkyu, Song, Taeseup, Hong, Seungki, Eito, S., Terashima, C., Han, Tae Hee, Kang, Jeung Ku, Fujishima, A., Kang, Yong Soo, Paik, Ungyu
• Format: Article
• Language: English
• ISSN: 2046-2069; 2046-2069
• DOI: 10.1039/C3RA46851H

To elucidate the influence of electrode geometry on the photocatalytic performance of TiO 2 , herein, we report the synthesis of three-dimensional in situ Gd-doped TiO 2 nanofibers (TiO 2 -NFs) using a simple electrospinning technique. The as-spun pristine TiO 2 -NFs show a higher photocatalytic (PC) activity ( k = 0.013 m −1 ) than the TiO 2 nanoparticles (TiO 2 -NPs) ( k = 0.006 m −1 ) electrode, which could be attributed to the fast electron transport in the 1D NFs. In addition, Gd-doped TiO 2 -NFs show nearly five-fold enhancement in the PC degradation rate due to synergistically higher electron transport and production of HO˙ due to the effects of morphology and doping, respectively. In striking contrast, Gd-doping has no influence on the PC activity of TiO 2 -NPs due to increased grain boundaries, signifying the vital role of the electrode architecture. The mechanism of Gd doping in pure anatase TiO 2 is investigated using density functional theory (DFT) calculations. The influence of Gd-doping and the electrode architecture on the charge recombination and flat-band potential variation in TiO 2 are discussed elaborately using ultraviolet photoelectron spectroscopy (UPS) and Mott–Schottky analysis, and the implications of these findings for designing doped 3D fibrous photoelectrodes are discussed.