Synergetic catalysis enhancement between H₂O₂ and TiO₂ with single-electron-trapped oxygen vacancy

The TiO₂-H₂O₂ system possesses excellent oxidation activity even under dark conditions. However, the mechanism of this process is unclear and inconsistent. In this work, the binary component system containing TiO₂ nanoparticles (NPs) with single electron-trapped oxygen vacancy (SETOV, V_O·) and H₂O₂ exhibit excellent oxidative performance for tetracycline, RhB, and MO even without light irradiation. We systematically investigated the mechanism for the high activity of the TiO₂-H₂O₂ under dark condition. Reactive oxygen species (ROS) induced from H₂O₂ play a significant role in improving the catalytic degradation activities. X-ray photoelectron spectroscopy (XPS) and electron paramagnetic resonance (EPR) results firstly confirm that H₂O₂ is primarily activated by SETOVs derived from the TiO₂ NPs through direct contribution of electrons, producing both ·O₂^-/·OOH and ·OH, which are responsible for the excellent reactivity of TiO₂-H₂O₂ system. This work not only provides a new perspective on the role of SETOVs playing in the H₂O₂ activation process, but also expands the application of TiO₂ in environmental conservation.