In situ Fe(III)-doped TiO2 mesocrystals catalyzed visible light photo-Fenton system

The difficulty of traditional Fenton reaction is the low conversion of Fe 3+ /Fe 2+ . The emergence of the photo-Fenton reaction can greatly improve the oxidation efficiency and Fe 2+ utilization rate to a certain extent, but this system is more complicated. Here, we used the in-situ iron (Fe) ions doped titanium dioxide (TiO 2 ) mesocrystals (MST) as a model to study in detail the effect of the catalyst's surface Fe site and oxygen defect on the photo-Fenton reaction. This in-situ doping strategy constructs oxygen vacancies (OVs) on the surface of MST to anchor Fe ions, thereby promoting the circulation of Fe 3+ /Fe 2+ . OVs form shallow energy levels in the conduction band of MST, enhancing the separation efficiency of photogenerated electrons and holes. The content of Fe ions can adjust the energy band gap of catalyst, which accelerating the transfer of photogenerated carriers on the surface with visible light. The strong interaction between OVs and Fe ions improves the synergy between photocatalysis and Fenton reaction. Under visible light irradiation, Fe x+ /MST exhibits efficient degradation of organic pollutants and mineralized intermediates under a wide range of pH conditions. This work provides a potential path to prepare efficient visible light photo-Fenton catalysts. • A facile method is proposed to prepare Fe(III)-doped TiO 2 mesocrystals. • Abundant oxygen vacancies are formed on the surface of TiO 2 mesocrystals. • Oxygen vacancies (O vs ) and Fe ions promote the circulation of Fe 3+ /Fe 2+ . • The Fe(III)-doped TiO 2 mesocrystals has excellent degradation performance.