The goal of this study is to provide insight into the mechanism of the oxygen reduction reaction on the TiO2 rutile (1 1 0) surface in the presence of bridging hydroxyl groups. Considering the Langmuir–Hinshelwood and Eley–Rideal mechanisms, each possible intermediate was identified using density functional theory and a cluster model along with the energy barriers of the reduction steps and the O[sbnd]O bond breaking. Our results show that the initial step, the O2 adsorption on the surface, is favored compared to the pure surface. At higher potentials, the oxygen reduction reaction was found to go through the formation of HO2, which can easily convert to two terminal hydroxyl groups. The rate-limiting step is the desorption of the first H2O with 0.58 eV energy requirement at zero applied potential, while at 1.23 V the reduction of the adsorbed OH to form H2O is the bottleneck with a barrier height of 1.71 eV.
ASJC Scopus subject areas
- Condensed Matter Physics
- Physical and Theoretical Chemistry