Enhanced Photoelectrochemical Properties from Mo-Doped TiO₂ Nanotube Arrays Film

• Main Authors: Danni Xue, Jie Luo, Zhong Li, Yanlin Yin, Jie Shen
• Format: Article
• Language: English
• Published: MDPI AG 2020-01-01
• Series: Coatings
• Subjects: tio₂; mo-doped; nanotube array; anodic oxidation; magnetron sputtering; photoelectrochemical properties
• Online Access: https://www.mdpi.com/2079-6412/10/1/75

Mo-doped TiO₂ nanotube arrays are prepared successfully by a combined method of direct current (DC) magnetron sputtering and anodic oxidation. The doping amount of Mo can be modified by changing the number of molybdenum blocks on the Ti target while a Ti−Mo alloy film is prepared by magnetron sputtering on a metal Ti substrate, following a Mo-doped TiO₂ nanotube array grown by anodization. Morphology test shows that the doping of Mo could inhibit the phase transition and growth of crystal of TiO₂. X-ray photoelectron spectroscopy (XPS) results show that Mo has successfully been embedded in the TiO₂ crystal lattice and mainly exists in the valence states of Mo⁶⁺. Mo-doping samples show slightly increased visible light absorption as the red shift of TiO₂ absorption edge with the band gap dropping from 3.24 to 3.16 eV with 0.5 at.% Mo doping. The enhanced photocurrent is demonstrated for a 0.5 at.% Mo-doped TiO₂ electrode. Through photoelectric performance testing under UV-visible light irradiation, the nanotube array film with a Mo-doped content of 0.5% produced the maximum photocurrent density, which is about four times the undoped TiO₂ nanotube array film, exhibiting a considerable photoelectric effect gain. The controllable Mo doping TiO₂ nanotube array film prepared by this combining technique is expected as a promising material for efficient applications in photoelectric conversion.