The Oxygen Reduction Reaction on Nb-doped Titanium Dioxide Single Crystal Electrodes

Abstract

Structural effects on the oxygen reduction reaction (ORR) have been studied on the low index planes of rutile TiO 2 doped with Nb (0.05-1 wt%) in 0.1 M HClO 4. The order of the ORR activity at 0.20 V (vs. RHE) is TiO 2 (100) < TiO 2 (111) < TiO 2 (110), and the activity increases with increasing Nb concentration. The activity of TiO 2 (110) is 5.6 times as high as that of TiO 2 (100) at Nb concentration 1%. The order of the ORR activity does not correlate with the amount of oxygen vacancy defects that are known as the active sites of the ORR of TiO 2 nanoparticles. The ORR activity of 1%Nb-doped TiO 2 (100) modified with melamine is 2.1 times higher than that of the unmodified one. The activity of 1%Nb-doped TiO 2 (110) modified with melamine is the highest in the low index planes of TiO 2. Modification by tetra-n-hexylammonium cation (THA +) affects the ORR activity slightly.

Degradation Analysis of Pt/Nb–Ti₄O₇ as PEFC Cathode Catalysts with Controlled Arc Plasma-deposited Platinum Content

“…1 However, electrocatalysts durability is ³ The content of this paper will be published by Yongbing MA as a PhD thesis at Yokohama National University in 2022. recognized as a limitation for their commercialization. [2][3][4][5] Carbon is a commonly used support for electrocatalysts in PEFCs owing to its numerous advantages, including high specific surface area, high conductivity, and commonly possessing functional groups that enable surface deposition of catalytically active materials. [6][7][8][9][10][11] However, the carbon supports used for PEFC cathodes undergo electrochemical corrosion during operation 12 caused by the oxidization of carbon under high potentials (standard electrode potential: 0.207 V vs. reversible hydrogen electrode (RHE)).…”