Electro-catazone treatment of an ozone-resistant drug: Effect of sintering temperature on TiO2 nanoflower catalyst on porous Ti gas diffuser anodes

Electrochemical heterogeneous catalytic ozonation (E-catazone) is a promising and advanced oxidation technology that uses a titanium dioxide nanoflower (TiO_2-NF)-coated porous Ti gas diffuser as an anode material. Our previous study has highlighted that the importance of the TiO_2-NF coating layer in enhancing OH production and rapidly degrading O₃-resistant drugs. It is well known that the properties of TiO_2-NF are closely related to its sintering temperature. However, to date, related research has not been conducted in E-catazone systems. Thus, this study evaluated the effect of the sintering temperature on the degradation of the O₃-resistant drug para-chlorobenzoic acid (p-CBA) using both experimental and kinetic modeling and revealed its influence mechanism. The results indicated that the TiO_2-NF sintering temperature could influence p-CBA degradation and OH production. TiO_2-NF prepared at 450 °C showcased the highest p-CBA removal efficiency (98.5% in 5 min) at a rate of 0.82 min^?1, and an OH exposure of 8.41 × 10^?10 mol L^?1 s. Kinetic modeling results and interface characterization data revealed that the sintering temperature could alter the TiO₂ crystallized phase and the content of surface-adsorbed oxygen, thus affecting the two key limiting reactions in the E-catazone process. That is, ≡TiO₂ surface reacted with H₂O to form TiO₂-(OH)₂, which then heterogeneously catalyzed O₃ to form OH. Consequently, E-catazone with a TiO_2-NF anode prepared at 450 °C generated the highest surface reaction rate (5.00 × 10^?1 s^?1 and 4.00 × 10^-3 L mol^-1 s^?1, respectively), owing to its higher anatase content and adsorbed oxygen. Thus, a rapid O₃-TiO₂ reaction was achieved, resulting in an enhanced OH formation and a highly effective p-CBA degradation. Overall, this study provides novel baseline data to improve the application of E-catazone technology.