A gas-solid and postsynthetic modification was proposed to enrich surface bridging hydroxyls (OHB) on TiO2 using ozone. It was found that the adsorbed ozone and its decomposition into oxygen atoms on oxygen vacancies would induce water dissociation and form OHB, narrowing the bandgap and enhancing the photoresponse. The increased OHB significantly doubled the efficiency of photogenerated charge carriers transfer, thus generating more reactive oxygen species. Additionally, OHB 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 OHB on TiO2 under mild conditions and insight into the mechanism underlying the process.
Key words
TiO2/Ozone treatment/Surface modification/Bridging hydroxyls/Photocatalytic oxidation of toluene/IN-SITU IR/TOLUENE DEGRADATION/OXYGEN VACANCIES/WATER/OXIDATION/TITANIUM/ADSORPTION/TIO2(110)/PHOTODEGRADATION/SPECTROSCOPY
NSTL
Elsevier