A series of CeO2-modified C3N4 (C3N4/CeO2X%) heterostructure photocatalysts was synthesized via a hydrothermal method. Their band structure was studied via theoretical calculation and experimental characterization. The behavior of charge carriers was investigated via absorption spectra, PL, and time-resolved PL decay curves. It was found that the modification of CeO2 on C3N4 matched the energy band, enhanced absorption in the visible region, separated photogenerated electrons and holes. Owing to the modification of CeO2 on C3N4, the photocatalytic performance was significantly improved as compared to that of C3N4. This study may offer a new strategy to fabricate and design a band structure of a new photocatalyst with high photocatalytic performance.
