Applying TiO2–x-Based Electrocatalysis and Photoelectrocatalysis Induced I–/IO3– Recycling for Green and Continuous Ozone Removal

Abstract

Solution absorption is a straightforward and efficient method for ozone treatment, but waste from inactive absorption solutions poses a risk of secondary pollution and raises the operating cost. Therefore, developing a sustainable recycling process for the absorption solution is essential for green ozone removal. In this study, we constructed a novel I^–/IO₃^– cycling system induced by electrocatalysis and photoelectrocatalysis to facilitate the reduction of KIO₃ in KI/KOH ozone absorption solution, thereby enabling absorption solution recycling. The stable operation of this system relies on high-performance cathode materials. By adjusting the concentration of oxygen vacancies on TiO₂, we reduced the energy barrier for IO₃^– reduction, optimized IO₃^– adsorption on the electrode surface, and improved the band gap structure of the electrode material, resulting in a TiO_2–x cathode with good IO₃^– reduction reaction (IO₃RR) performance. Notably, this method achieves an ozone removal cost of $3.72 per kilogram, only one-third of the cost associated with conventional catalytic ozone decomposition. This approach provides a promising new direction for green and efficient ozone removal.