Preparation and Photocatalytic CO Oxidation Performance Study of Au/Oxygen-Deficient (Anatase/B-Phase) TiO2 Heterojunction Microspheres

Multi-heterojunctions are more promising than single heterojunctions in photocatalysis due to the availability of more interfaces between each component. However, photocatalytic activity is highly dependent on the contact mode of individual components. In this work, we assembled gold nanoparticles/oxygen-deficient (anatase/B-phase) TiO2multi-heterojunction microspheres using spray pyrolysis and focused on their contact mode-governed photocatalytic activity. The results reveal that using oxygen-deficient (anatase/B-phase) TiO2microspheres as building blocks could significantly enhance the absorption of visible light and the photocatalytic activity of a gold–TiO2system toward the photocatalytic carbon monoxide oxidation. Furthermore, loading gold nanoparticles onto B-phase TiO2could facilitate a more prominent enhancement of activity than that of pure B-phase TiO2, benefiting from the two-electron reduction of oxygen at the interface of TiO2/Au. Meanwhile, the high crystallinity of B-phase TiO2microspheres allows for a gold loading amount of 1 wt% in the gold/(anatase/B-phase) TiO2system, which is 1.67 times more active than pure B-phase TiO2microspheres, in the photocatalytic oxidation of carbon monoxide to generate carbon dioxide.Keywords:photocatalytic carbon monoxide oxidation;B-phase TiO2;oxygen-deficient;microspheres