Figure 4. Dose-dependent effects of H₂O₂ on reactive oxygen species (ROS) generation from irradiated TiO₂. The ESR spectrum of irradiated (365 nm) TiO₂ (0.15%, wt/vol) measured by EPR spin-trapping following the addition of different concentrations of H₂O₂ (0.0003%–30%) at 1 min and with DMPO (880 mM) as the spin trap.