No abstract

No abstract

No abstract

Four TiO 2 electrodes have been investigated for the oxygen reduction reaction (ORR) in 2 M NaOH. Anodic oxidation of Ti-foil was used as the final or the first step in the preparation of four electrodes based on TiO 2 : amorphous (Ti/AM-TiO 2 ), two anatase forms (Ti/A400-TiO 2 and Ti/A550-TiO 2 ), and, finally, lithium-anatase form (Ti/A-Li 0.25 TiO 2 ), all of them obtained as TiO 2 nanotube arrays. The electrodes' structure was examined by Raman spectroscopy. Cyclic voltammetry and chronoamperometry were employed for the study of kinetics of ORR. Ti/A-Li 0.25 TiO 2 and Ti/A400-TiO 2 electrodes showed the highest catalytic activity for ORR with the highest cathodic peak current density and the lowest Tafel slope values. Number of electrons exchanged during ORR at TiO 2 electrodes was in the range from 2.3 to 2.8. Additionally, TiO 2 electrodes showed good stability as well as acceptable selectivity in the presence of borohydride, methanol or ethanol as typical fuels for fuel cells. Thus this study introduces a simple, low-cost preparation route of TiO 2 -based electrodes with high efficiency for ORR for energy conversion and storage applications.

No abstract