Publications Repository - Gdańsk University of Technology

Titania (titanium(IV) oxide) is a highly active, stable, cheap and abundant photocatalyst, and is thus commonly applied in various environmental applications. However, two main shortcomings of titania, i.e., charge carrier recombination and inactivity under visible-light (vis) irradiation, should be overcome for widespread commercialization. Accordingly, titania has been doped, surface modified and coupled with various ions/compounds, including narrower bandgap semiconductors, such as oxides of copper and silver. Unfortunately, these oxides are not as stable as titania, and thus loss of activity under long-term irradiation (photo-corrosion) has been observed. Therefore, this study has focused on the preparation of stable coupled photocatalysts, i.e., CuxO@TiO2 core–shell nanostructures, by the microemulsion method from commercial Cu2O as a core and TiO2 (ST01-fine anatase) as a shell. The photocatalysts have been characterized by DRS, SEM, TEM, XRD, XPS and reversed double-beam photo-acoustic spectroscopy (RDB-PAS) methods, and activity tests under UV (anaerobic dehydrogenation of methanol and oxidative decomposition of acetic acid) and vis (phenol oxidation) irradiation. The higher activities of coupled photocatalysts than their counterparts have been found in all studied systems under UV/vis irradiation. Moreover, long-term experiments (10 h) have shown high stability of CuxO@TiO2. However, the change of oxidation state of copper has also been observed, i.e., to negative and positive values, confirming the charge transfer according to the Z-scheme under UV irradiation and type-II heterojunction under vis irradiation, respectively. The property-governed activity and the mechanism have been discussed in detail.

Authors

• Kunlei Wang,
• mgr inż. Zuzanna Bielan link open in new tab ,
• Maya Endo-Kimura,
• Marcin Janczarek,
• Dong Zhang,
• dr inż. Damian Kowalski,
• prof. dr hab. inż. Anna Zielińska-Jurek link open in new tab ,
• Agata Markowska-Szczupak link open in new tab ,
• Bunsho Ohtani,
• Ewa Kowalska