Higher water splitting hydrogen generation rate for single crystalline anatase phase of TiO2 nanotube arrays
School of Materials and Mineral Resources Engineering, Universiti Sains Malaysia, Engineering Campus, 14300 Nibong Tebal, Seberang Perai Selatan, Pulau Pinang, Malaysia
a e-mail: firstname.lastname@example.org
Revised: 2 August 2012
Accepted: 3 August 2012
Published online: 3 September 2012
This paper presents a detailed investigation on the effect of heat-treatment process on the highly ordered titanium dioxide (TiO2) nanotube arrays in connection with the photoelectrochemical (PEC) response and hydrogen evolution rate. TiO2 nanotube arrays have been systematically heat-treated to control the transformation of as-anodized TiO2 amorphous structure to crystalline anatase and rutile phases. In this study, single crystalline TiO2 anatase phase exhibited a higher PEC response and hydrogen evolution rate at 400 °C heat treatment. The photocurrent density increase was mainly attributed to the effective transport of photo-induced electrons within the single crystal anatase phase. However, polycrystalline anatase and rutile phases showed the fluctuation in lower photocurrent density upon heat treatment above 500 °C. The mobility of photo-induced electrons was obviously hindered due to the recombination losses in defect sites between the anatase and rutile phase.
© EDP Sciences, 2012