The spontaneous formation and long-term surface stabilization of superoxide radicals are observed on specific TiO2 hybrid materials in which titanium is coordinated to an organic ligand. Here the rationale for this uncommon phenomenon is investigated by a synergistic theoretical and experimental approach involving density functional theory (DFT) calculations and spectroscopic techniques. Stoichiometric and reduced anatase (101) surfaces modified with acetylacetone, dibenzoylmethane, and catechol are comparatively examined. These results reveal that the interaction between organic ligands and adsorbed O2 molecules improves when O vacancies are present on the external layer of the surface, promoting O2 reduction. The electronic features of the ligand play a pivotal role for both an effective electronic interaction with the surface and the stabilization of the generated reactive oxygen species. These results agree with experimental data showing that sol–gel-derived Ti-diketonate hybrid oxides spontaneously produce very persistent superoxide radicals under ambient conditions, thus holding a high intrinsic oxidative activity.
|Original language||English (US)|
|Journal||Advanced Materials Interfaces|
|State||Published - Aug 8 2021|
Bibliographical noteKAUST Repository Item: Exported on 2021-08-10
Acknowledgements: I.R. and C.I. contributed equally to this work. I.R. thanks MIUR and European Union for AIM-International Attraction and Mobility Call for Researchers funded by PON RI 2014–2020. The authors thank Prof. Gerardino D'Errico of the Department of Chemical Sciences of the University of Naples Federico II for providing the access to EPR instrument and for the help in EPR investigation. For computer time, this research used the resources of the KAUST Super-Computing Laboratory (KSL) at KAUST.
ASJC Scopus subject areas
- Mechanics of Materials
- Mechanical Engineering