Factors affecting oxygen reduction activity of Nb2O5-doped TiO2 using carbon nanotubes as support in acidic solution

• DOI: 10.1016/j.electacta.2018.07.082
• Publication Date: 2018-07-19T23:10:00Z
• Authors: Akimitsu Ishihara; Chumeng Wu; Takaaki Nagai; Koji Ohara; Kengo Nakada; Koichi Matsuzawa; Teko Napporn; Masazumi Arao; Yoshiyuki Kuroda; Satoshi Tominaka; Shigenori Mitsushima; Hideto Imai; Ken-ichiro Ota
• Keywords: [CHIM] Chemical Sciences; [CHIM]Chemical Sciences; 01 natural sciences; 0104 chemical sciences

Abstract In order to develop stable non-platinum cathodes based on group 4 and 5 metal oxides, we investigated factors affecting the use of Nb2O5-doped TiO2 for the oxygen reduction reaction (ORR). Multi-walled carbon nanotubes (MWCNTs) were used as support to maintain sufficient electrical conductivity. Nb2O5-doped TiO2/MWCNTs prepared by hydrolysis was heat-treated at the desired temperature for a certain time under argon containing 4% hydrogen to investigate the relationship between ORR activity and physicochemical properties such as crystalline structure and electronic state. We confirmed that the density of the low-valence state of titanium ions, Ti3+, affected ORR activity. In addition, crystalline distortion of Nb2O5-doped anatase might be essential in order to show ORR activity.