Enhanced Photocatalytic Ozonation Using Modified TiO₂ With Designed Nucleophilic and Electrophilic Sites

Photocatalytic ozonation is considered to be a promising approach for the treatment of refractory organic pollutants, but the design of efficient catalyst remains a challenge. Surface modification provides a potential strategy to improve the activity of photocatalytic ozonation. In this work, density functional theory (DFT) calculations were first performed to check the interaction between O₃ and TiO₂-OH (surface hydroxylated TiO₂) or TiO₂-F (surface fluorinated TiO₂), and the results suggest that TiO₂-OH displays better O₃ adsorption and activation than does TiO₂-F, which is confirmed by experimental results. The surface hydroxyl groups greatly promote the O₃ activation, which is beneficial for the generation of reactive oxygen species (ROS). Importantly, TiO₂-OH displays better performance towards pollutants (such as berberine hydrochloride) removal than does TiO₂-F and most reported ozonation photocatalysts. The total organic carbon (TOC) removal efficiency reaches 84.4 % within two hours. This work highlights the effect of surface hydroxylation on photocatalytic ozonation and provides ideas for the design of efficient photocatalytic ozonation catalysts.