Open AccessBlue TiO2 nanotube arrays as semimetallic materials with enhanced photoelectrochemical activity towards water splitting
Author(s) -
Naeimeh Sadat Peighambardoust,
Umut Aydemir
Publication year - 2020
Publication title -
turkish journal of chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.239
H-Index - 46
eISSN - 1303-6130
pISSN - 1300-0527
DOI - 10.3906/kim-2004-85
Subject(s) - photocurrent , water splitting , annealing (glass) , polarization (electrochemistry) , nanotube , photoconductivity , chemistry , doping , charge carrier , nanotechnology , materials science , carbon nanotube , optoelectronics , chemical engineering , photocatalysis , composite material , catalysis , biochemistry , engineering
In the past years there has been a great interest in self-doped TiO 2 nanotubes (blue TiO 2 nanotubes) compared to undoped ones owing to their high carrier density and conductivity. In this study, blue TiO 2 nanotubes are investigated as photoanode materials for photoelectrochemical water splitting. Blue TiO 2 nanotubes were fabricated with enhanced photoresponse behavior through electrochemical cathodic polarization on undoped and annealed TiO 2 nanotubes. The annealing temperature of undoped TiO 2 nanotubes was tuned before cathodic polarization, revealing that annealing at 500 °C improved the photoresponse of the nanotubes significantly. Further optimization of the blue TiO 2 nanotubes was achieved by adjusting the cathodic polarization parameters. Blue TiO 2 nanotubes obtained at the potential of –1.4 V (vs. SCE) with a duration of 10 min exhibited twice more photocurrent response (0.39 mA cm -2 ) compared to the undoped TiO 2 nanotube arrays (0.19 mA cm -2 ). Oxygen vacancies formed through the cathodic polarization decreased charge recombination and enhanced charge transfer rate; therefore, a high photoelectrochemical activity under visible light irradiation could be achieved.