Catalyst-Doped Anodic TiO₂ Nanotubes: Binder-Free Electrodes for (Photo)Electrochemical Reactions

• Main Authors: Hyeonseok Yoo, Moonsu Kim, Yong-Tae Kim, Kiyoung Lee, Jinsub Choi
• Format: Article
• Language: English
• Published: MDPI AG 2018-11-01
• Series: Catalysts
• Subjects: TiO₂ nanotubes; anodization; doping; water electrolysis; photoanodes
• Online Access: https://www.mdpi.com/2073-4344/8/11/555

Nanotubes of the transition metal oxide, TiO₂, prepared by electrochemical anodization have been investigated and utilized in many fields because of their specific physical and chemical properties. However, the usage of bare anodic TiO₂ nanotubes in (photo)electrochemical reactions is limited by their higher charge transfer resistance and higher bandgaps than those of semiconductor or metal catalysts. In this review, we describe several techniques for doping TiO₂ nanotubes with suitable catalysts or active materials to overcome the insulating properties of TiO₂ and enhance its charge transfer reaction, and we suggest anodization parameters for the formation of TiO₂ nanotubes. We then focus on the (photo)electrochemistry and photocatalysis-related applications of catalyst-doped anodic TiO₂ nanotubes grown on Ti foil, including water electrolysis, photocatalysis, and solar cells. We also discuss key examples of the effects of doping and the resulting improvements in the efficiency of doped TiO₂ electrodes for the desired (photo)electrochemical reactions.