DFT study of molecular hydrogen interaction with photoexcited TiO2 surface: Nanocluster model

- We perform DFT study of H2 interaction with photoexcited triplet Ti8O16 nanocluster.
- Three scenarios are revealed: repulsion, physisorption, and dissociative photoadsorption.
- H2 physisorption is barrierless and exothermic (ΔH0 from −0.02 eV to −0.11 eV); exothermic dissociative H2 photoadsorption (ΔH0 = −H0 = −0.85 eV) proceeds via barrier (0.04 eV).
- The calculated Ti3+g-tensors match experimentally observed surface Ti3+ EPR signals.
- Oxygen hole stability affects neither energetics nor a mechanism of dissociation.