The fabrication and characterization of CeO2/Cu2O nanocomposites with enhanced visible-light photocatalytic activity

Spherical Cu2O nanocrystals were synthesized and CeO2/Cu2O nanocomposites were successfully prepared from the spherical Cu2O nanocrystals. Characterization analysis was performedviascanning electron microscope (SEM), transmission electron microscope (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and UV-visible diffusion reflectance spectroscopy (DRS) studies. In comparison with the Cu2O nanocrystals, the CeO2/Cu2O nanocomposites exhibited high visible-light-induced photocatalytic activity for the degradation of methyl orange solution. Radical trapping experiments proved that photo-generated electrons played a very minor role, while photo-generated holes and superoxide radicals played a major role in the degradation process. The CeO2/Cu2O system could cause the internal energy band to bend, leading to the building of internal electric fields. The excited electrons and holes easily moved in opposite directions, promoting the effective separation of charges, which obviously enhanced the visible light photocatalytic activity of the catalyst.