Photoelectrochemical performances of TiO2 nanotube arrays hydrothermally treated in sulfide

Anatase TiO2 nanotube arrays were hydrothermally treated in Na2S solution, and the photoelectrochemical performances were systematically studied. Morphology, structure, elemental component and photoelectrochemical performances of TiO2 were characterized by scanning electron microscope, high resolution transmission electron microscope, X-ray diffractometer, X-ray photoelectron spectrometer and electrochemical workstation, respectively. The influence of the sulfide treatment on the photoelectrochemical performance is discussed in detail by measuring cyclic voltammogram, chornoamperogram and chemical impedance spectrum of treated TiO2 nanotube arrays in different conditions. TiO2 nanotube arrays sulfide treated in 30 mM Na2S solution at 135 degrees C possess the highest photocurrent of 289 mu A, which is 3.3 times that of untreated sample. High optical absorption, large electrochemical active surface area and rapid electron transfer rate due to the mesoporous structure rather than sulfide dropping play key roles in enhancing the photoelectrochemical activity of the TiO2 nanotube arrays. (C) 2015 Elsevier B.V. All rights reserved.