Effective regulation of surface bridging hydroxyls on TiO2 for superior photocatalytic activity via ozone treatment

A gas-solid and postsynthetic modification was proposed to enrich surface bridging hydroxyls (OH B ) on TiO 2 using ozone. It was found that the adsorbed ozone and its decomposition into oxygen atoms on oxygen vacancies would induce water dissociation and form OH B , narrowing the bandgap and enhancing the photoresponse. The increased OH B significantly doubled the efficiency of photogenerated charge carriers transfer, thus generating more reactive oxygen species. Additionally, OH B provided more adsorption sites for toluene, contributing to the excellent activity and stability. The degradation pathways of toluene containing OH addition and hydrogen abstraction were proposed based on in situ DRIFTS results. Ozone treatment was more effective than other reported surface treatments, and presented a universal improvement on both gas-solid and liquid-solid photodegradation. This work provides a facile, effective, and alternative strategy for the targeted regulation of OH B on TiO 2 under mild conditions and insight into the mechanism underlying the process. • Bridging hydroxyls were regulated using ozone at mild conditions. • Rich bridging hydroxyls doubled charge carrier separation and transfer efficiency. • Oxidation of toluene and its intermediates were accelerated via OH addition. • Modified TiO 2 exhibited superior activity and stability for toluene degradation.