Hybrid metal oxides quantum dots/TiO2 block composites: Facile synthesis and photocatalysis application

Two kinds of hybrid metal oxide quantum dots, CuxO and FexO, were successfully anchored on TiO2 blocks by a facile, low-cost and large scale reflux method. The resultant photocatalysts (CuxO/TiO2 and FexO/TiO2) were characterized by transmission electron microscope (TEM), Brunauer–Emmett–Teller (BET), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and UV–vis absorption spectrum, and their photocatalytic performances were evaluated by photocatalytic decoloration of methylene blue (MB) solution under simulated sunlight and visible light (λ > 420 nm) irradiation. The results showed that hybrid metal oxide quantum dots CuxO (or FexO) were dispersed uniformly on TiO2 blocks. Both Cu and Fe are in mixed valences state (Cu+ and Cu2 +, Fe2 + and Fe3 +, respectively). CuxO/TiO2 and FexO/TiO2 demonstrated high photocatalytic ability whether they were under simulated sunlight or under visible light (λ > 420 nm) irradiation, which can be confirmed from the measurement of the amount of hydroxyl radicals (OH). Based on the above results, the mechanisms of enhanced photocatalysis on CuxO/TiO2 and FexO/TiO2 under simulated sunlight and visible light were proposed.