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 performed via scanning 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.